No idea where to begin!

The reason I say no to sanding to bare metal is
If it is in sound condition ,the original factory paint makes a good base starting point.
If the car has been hack at and painted before and there is bubbles, shrinkage and
a lot of filler in there and so on then it might be good to go to bare metal.

But that is a lot of work and then prime bare metal with epoxy primer as soon as you
can.
I am no expert by any means but I started just like you are.
I am 49 years old and am self taught. Painted many cars since my early 20's.
Had a lot of mistakes along the way.

If you are determined GO FOR IT! You will learn along the way.

Darryl