A Bezier path is one that has not been created with the parametric shape tools. That is, circle/oval, square/rectangle, star, etc.
These things are not Bezier paths:
If you've created your shape with one of those, you might need to convert it to Bezier.
Here is the option for it:
Note that you have to right-click on the path itself, not the shape group.
That being said, I'm not sure this is the problem you're experiencing. If this isn't what you're looking for, let us know. Screenshots of your attempts to do things can be very helpful.
As it turns out, my shapes are already Bezier. Which is why I don't have the option to convert to bezier
Convert a shape path to a mask path by copying the shape’s path to the Mask Path property
^ This was literally all the information I could find, just reworded in different ways... OH MY GOD I JUST FIGURED IT OUT. That's usually how it goes, I'll fight with it for ages but I won't solve it until I post a question about it.
I had been using the keyboard shortcut for copy, I had no idea there were other kinds of copying...
I need to be using the second one. Can't believe this wildly important detail was left out of literally every post/video I could find! Which was a lot. Thank god this is over.
Thanks again for the help!
I'm glad you got it working!