No idea where to begin!

I bought the 3m paint and rust stripper and man does that thing work great! luckily there wasn't too much paint on the car... looks like rattle can grey primer, yellow paint, primer and then metal.

my question now is, do I use the wax and grease remover before I sand? Or after I sand?

I know I said I sanded already but I just did a little part on the fender panel, to see how it works. read on car craft to use some scoth brite afterwords to kinda fine it out.

Also seeing im gonna go through the whole car and take it down to bare metal, fix dents and rust patch. I know its probably gonna take me about 2 weeks to sand it down so I will have bare metal exposed. On one of the dvd's I was watching it said that if your not gonna be able to get to that panel in a while after its been sanded to spray some metal finish on it to protect it.

do you think I should buy some?