This exact thing just happened to me. When you purchase the Photography package, it first downloads Lightroom CC, which is a cloud based platform. You then have to also download and install the Lightroom Classic (and you can also download and use Photoshop as part of the $9.99 package.).
Once you download the Classic Lightroom everything will look familiar.

I am a long time Aperture user. For many years I resisted Lightroom. I didn't even use it when someone gave it to me as a present. I was very disappointed when Apple closed its Aperture department, in favor of creating something for most people, rather than pros. So I no longer had a choice and decided to switch. Lightroom is amazing and I am so happy that I converted over. It is not as difficult as Photoshop and many of the adjustments are intuitive. You will have far better results with photos in Lightroom than Aperture. In fact, I ended up going back to my favorite photos and starting from scratch with Lightroom readjustments, rather than keeping the Aperture final photos. I'm not going to tell you the transition will be easy, it will take some time to get used to it (probably 6 months to a year). But, in the end, you will never look back. My suggestions:

1. First focus on photo organization. I spent a full week watching you-tube video and reading articles on file management. Lightroom has many advantages. Unlike with Apple, where you have less control of how files are stored, you can create a designated hard drive. I set up a 4TB hard drive only for Lightroom photos (and that is back up through time machine). If I remember correctly B&H has some great instructional videos on how to download and name your files, how to use keywords, etc. I have mine all organized by date, and subject. It is so easy to find things. The only advantage that Aperture has is that it worked seamlessly with iMovie. Although I can bring photos in from Lightroom, the Aperture library was always easily available. Copying and transferring files from Lightroom is much easier. You can always see the files, even outside of Lightroom, by clicking on the hard drive. You will have so much more control.

2. Once you master downloading and organization, then start to migrate photos over. There are a lot of articles on converting from Aperture to Lightroom. Because my organization is based on date, migrating over helped me organize and get rid of and clean up my photos. There are way to migrate adjusted photos or the original photos. It is a little complicated, so make sure you back everything up before trying.

3. Watch you-tube videos on how people adjust photos in Lightroom. You can come up with a very simple checklist of adjustment. After a while you will be amazed at how much your final product improves. There is so much more depth in Lightroom than Aperture. You can limit it to just a few adjustments or you can get very creative.

There are probably other great programs out there. But from my experience Lightroom was a real winner. Good luck.

Hair are some pics. Same English Goldendoodle in the span of one year.

Nice shots. How did you manage to get above the eagle? I'm always shooting up. Cool perspective.