Beginners Guide to Mac

I am converting from a PC to Mac and having trouble adjusting. Where can I find a crash course to my Mac book? I do very well with videos, I am not great at reading and retaining anything on a manual. In all honesty, I've had my Mac Book Pro for a few years and hardly ever used it. Now that I am trying to do anything, it seems like everything is out of date or not synced. When I open the App Store it says there are no updates. I'm in the process of downloading IOS Catalina, but it is taking FOREVER. I'm just wondering what else can I do to improve the function of my Mac. Thank you for any help you can offer.