Before you start using Lightroom you need to create a file system that works for you.

Do you want:

the year to be the top folder and events spepararte folders in it, like Family, Vacations, Christmas, etc or do you prefer

Family-> 2018, 2017, 2016 etc.
Vacations-> 2018, 2017, 2016 etc. and so on.

You need a system that works for you outside of Lightroom.

Once you have a system set up you can either download files from your camera/card into those folders through the computer operating system and then import into LR or you can have LR download the files from your camera/card into the computer and then import into LR. When you import into LR all you are doing is telling LR and the LR catalog system where your files are. It is imperative that you know how to find your files without LR.

http://www.jkost.com

Julieanne Kost is Adobe's master trainer. She knows Lightroom better than any other trainer outside of Adobe. Her videos can walk you through the entire application and show you what the tools can do.

Adobe also has some of her videos on their site, as does Lynda.com.

Tony Northrup has an excellent video tutorial series, too:

https://northrup.photo/product/lr/

I can't stand the way Scott Kelby writes, or I'd recommend his stuff, too.

Pay particular attention to the STRUCTURES you put in place to house and organize your images. Remember, when you "import" an image, it stays where it is. Lightroom Classic CC simply stores a LINK to it in its CATALOG (which is really a database of sorts). Make sure you move all your images off of your camera's SD or CF card, onto a drive that will remain their resting place, at least until you're done with them. That will help LR maintain its links.

Lightroom never changes an original image, whether it is a raw file or a JPEG or TIFF image file. You are always looking at a freshly-generated PROXY image. The catalog database "saves" (stores) your changes automatically, just like any database you may be familiar with. The only time those changes actually are applied to the file is when you EXPORT a copy of it, PRINT a copy of it, or POST a copy of it to a web site.

OMG, I've been muddling through the trial subscription of LR for 3 days and I am making very little progress. Yes, I've listened to many of the tutorials. Is there something one of you could recommend for a new beginner? I have managed to import a few photos. One I even love! BUT I want to import more. And I think I'm doing everything I'm supposed to but then I can't find them. Where did they go? What am I doing wrong? Many thanks! (Should probably add that I am using Lightroom Classic CC.)

Forget the tutorials and get one of the books, such as Scott Kelby's.

Tutorials and YouTube videos can be fine to learn a specific technique or task, but I find a good reference book invaluable to learn a complex new program quickly. It's most certainly an overwhelming task to try to teach via a forum! In fact, I usually recommend buying the book and at least doing a quick read of it BEFORE starting a trial subscription, to get the best out of the 30 days you have to test drive the software. Too late for that now, so just scramble and buy a book, use a fast shipping option and get busy studying it ASAP.

To get you started locating your images, first you'll need to know where they are on your computer.

1. Go to LR's Library Module and click on Import Images.
2. LR will look for a memory card, but in the upper left corner of the import dialog box you'll see a list including "other location". Click that.
3. Another box with a map of your computer will open... use that to locate the images and tell LR where to import from.

You actually don't need LR to move your images to your computer from your memory card. You can do that easily with your computer's operating system, copying the images into folders you create yourself. Then you do the LR Import as a separate function, as described above.

But by default LR will start up and try to Import images any time you insert a memory card into the computer. I turn this off, but it's also possible to just cancel it, do the copying of the files from memory card to computer as described instead.

If you let it, LR also will automatically create folders where it will place the Imported images. This may be somewhere other than where you've been putting your images, and the folders may be named differently that what you usually do.

LR doesn't actually "contain" your images... it creates a thumbnail and data set that it associates with the original image file, which can be anywhere on your computer or even on an external drive, the "cloud" or whatever.

Hopefully this will help you get started.... but you still need the book because there's A LOT more to learn and not much time to do so!

Hint: If using a Windows PC while working within LR, one of the most powerful "tools" is a "right click". Many places throughout the program that will call up a menu that allows you to initiate some action. In the Library module, if a file or folder is grayed out and there's a question mark next to it, that means LR is unable to find it for some reason. Might be that you moved it using something other than LR.But a right click on the grayed out file or folder will open a short menu that includes "locate missing file/folder". Click on that and a dialog box opens.

Another example, in the Develop module, after working on an image you can right click on it and another menu will pop up that includes several possible actions including "send to another software (such as Photoshop)" or "export image", . Choosing "export" opens the export dialog box which has a large number of options to be set, such as how big to make the image, quality, whether to add a watermark and more. It also may you specify if the exported file is to be sent to a folder on your computer or other destination (for example I have LR plug-ins that allow me to export directly to a couple sites online: Flickr and Exposure Manager).

There are also a number of time-saving keyboard shortcuts available, as well as little "arrows" or "triangles" scattered around LR that serve various functions (hide/show a panel of tools, header or film strip... or let you set up what navigation tools are displayed, etc.)

I haven't used a Mac in a couple decades, so am not sure how different they might be now. But I'm sure there is some means of doing much the same functions in LR.

P.S. LR really isn't intended to "finish" images to high quality. It's mostly a powerful organizer, cataloger and digital asset management program... with "lite", fast image editing tools to make "proof" quality output. It's designed to work hand-in-hand with Photoshop, which is the "Mac Daddy" of all image editors with minimal, "lite" organizing capabilities. If you subscribe, you'll get both. But if you think LR is intensive, just wait til you see Photoshop! It's probably 5X as complex and challenging to learn. In comparison, LR is a piece of cake to learn. So, just take it all one step at a time.

If it all gets too overwhelming or seems like way more than you need... you might want to do a trial of Adobe Elements. It's more of an "all in one" program and has a lot of built-in support (which both LR and PS completely lack). MUCH easier to just jump into Elements and start using it. But there are some good books (and tutorials, etc.) to help get up to speed quickly with Elements, too. (There are various plug-ins available for Elements, too... though not as many as there are for LR and PS).

Enjoy LR, it is very powerful and easy to use. There is a lot to learn and besides all of the free videos, there are many good books to buy as a reference. Scott Kelby produces books on LR and PS when you move into it. He writes very clearly and makes learning easy. He also will tell you this is my way but here are some others. The advice about 1 instructor is sound, at least until you have a solid knowledge base.
Also, there is a section devoted to post processing here on the hog. They are very helpful.
Good luck. Pm me if you have any questions.