The best way on this- short of getting a person that knows to sit down with you- is just play with it. Put it on the machine & see how things go on plain fabric. Get a cheap zipper & follow the instructions & practice.
My first machine the zipper foot was merely short on one side, it had a dimple underneath but it wasn't well designed and I hated zippers because they always looked like crap.
My new machine, the zipper foot has a sort of hollow bridge like shape underneath that runs right over the zipper teeth
like a train on a track- my zippers come out looking beautiful!
The other zipper trick I learned was start at the top & sew down, then go back & start at the top again
on the other side & sew down. Sewing like the zipper instructions say, (down, across & up the other side) nearly always results in a puckered zipper covering.
You can use a zipper foot for anything else that has lumpy or thick trim like piping, beaded fringe, beaded trim or ribbon, etc. I use mine quite frequently.