BUT you should definitely spend your time going through the information on https://www.motionscript.com/. Start with Mastering Expressions. Of course, there are a lot of other useful things on Dan’s site that you can use right out of the box. However, if you want to LEARN expressions, start with Mastering Expressions.
When you have a lot of trouble solving your expressions problems, post back here for encouragement and support!
It really depends whether you have any prior programming language experience, logical muscle ready for that, or not. If not – then general course will do great for starters. If yes – then more specifics on expressions would be the way to go.
Most importantly – practice, practice and practice. Don’t just watch courses – re-write whats being shown. That is the fastest way towards mastery. You learn not only by watching, but doing simultaneously – twice the speed.
Then, put that practice to actual experimentation with things – knowledge without practical usage rusts faster than you expect it to do 🙂