Hi.
What device are you using to take pictures? Phone? (iPhone?), camera? What. Do you also have an iPad? If you are using iPhone or iPad, you should consider using (and paying (a small amount) for) iCloud photos to keep your photos in sync accross all your devices.
If you are learning from scratch, there is a lot to be said for starting with Apple photos. It is there, you don't have to pay for it, it will do most of what you want - and there is lots of support.
When you've learned to use that, you'll have a much better idea of what you want to be able to do, whether the apple software can do it and whether you want to move on to bigger and better (and more expensive)
Youtube can be a great place for tutorials - though they vary a lot in quality. But they have the advantage that you can actually see what is happening, rather than having to imagine it from words and pictures.
As regards tutorials - here is a really useful search on apples own youtube channel. Just beware of anything older than a year, as it might start to look different from what you have on your new mac.
https://www.youtube.com/c/applesupport/search?query=photos
After that this youtube search lists a lot. Start with shorter ones on more basic topics. Try stuff out. If they spend too much time waffling, just move on to one that gets to the point quicker.
https://www.youtube.com/results?search_query=apple+photos+tutorial+2020
Good luck.