how would you get started learning these things? I've always wanted to do something like this but I don't know what begin with
There's not really much more to it than that.
You may need to learn a ton as you go if you don't know the basics of the area the project is in. Software based projects are probably easier than hardware based projects in the sense that you won't lose money to change your mind.
On a RPi, you can always just rewrite the SD card and carry on. No harm, no foul. You're not counting on it like you would your main machine (until you are).