I was wondering if after I clay bar the car, do I have to polish it or can I just wax it? what will be the difference? thanks in advance.

no difference, the claybar will do all of the work any way you go with that one.

you NEED to polish it if you wax it the clay get damaged

You are on the right track, wash it well, clay the surface to get rid of all the surface contamination and to get the paint glossy smooth, then follow with polish, polish feeds the paint and protects it, you can stop there, if you wish you can follow the polish with a wax, I dont use carnuba based waxes anymore I prefer polymer waxes, they last longer and dont build up and protect the paint better. My favorite is the Klasse all in one polish and the Klasse polymer glaze. You can get both over the internet.

Just do it in exactly that order. Wash it good, then use the clay with the spray detailer, then wax it. It'll look awesome and feel soooo smoooooooth. If you don't have the spray solution, you can also wash it then use the clay with the leftover soapy water and then rinse off with water before waxing. Just make sure you are out of the sun when you do it. If you just wax after washing without the claybar, it won't have that glassy feeling when you run your hand over ir.When you use the claybar, it leaves the surface super clean and free of any particles that stick to the car, making waxing a much more easier job.Just don't drop the claybar, and don't use it everytime you wash the car. Keep a small ziplock sandwich bag handy so you can store the clay or if you have to put it down.