I have a rotel ra-01 and I have an integrated phono. I'm not sure how to put the ground wire of my turntable into the ground of the amp. When I unscrew the screw I see 2 parts , a metal screw (that i unscrewed) and a small round piece with teeth that is seperate. Normally the 2 pieces are stuck together when I look at other amps but they are seperate on mine. Should I put the ground wire between this piece and the screw or after both pieces where the ground wire will touch the back of the amp?

As long as the wire is making contact with metal you should be fine

One problem with the attached toothed washer is that the wire may not make solid contact, lying in the notch between two adjacent teeth. If you don't want to put a ring or spade terminal on the ground, and it is thin enough, try to slip it between the knob and the flat side of the washer. Then, when you tighten the knob, the wire is squeezed against the washer, giving a solid contact, and a good ground for your TT. YMMV

i'm not sure that I understand.

if you look at the pro-ject phono box so that I can explain myself easier

http://www.project-audio.com/bilder/phonoboxv.jpg

if you look at the ground i have a screw similar to this one where you are able to unscrew it backwards but then a second ring with "teeth" is revealed and this piece is seperate from the screw and you can move it around. The other difference is that there is no metal that touches the amp like this one has. I'm guessing I have to plug the ground wire between the screw that i pulled back and the ring with teeth so that the metal of the ring with teeth can make contact with the amp. I tried doing this and it was fine but even when I put in the ground wire of the turntable at the end of these 2 pieces it still works fine.