If you have used any Windows from XP upto 8 you will know quite a lot already when you begin to us Win 10.
In practice Win 10 is just a different skin but with the same ingredients behind it, in my opinion it is a great improvement, it is much faster and easier to learn.
If you learn how to use all the shortcuts this will go a long way to help you find you way round.
I will one very useful tip which I use all the time, instead of clicking on the Windows icon in the bottom left corner do this instead:

Mouse into the bottom left corner until it disappears.
Now right click your mouse.
You will now see a pop up of 18 options from Desktop to Programmes and Features.
This is a far quicker method than using the Metro screen.