Need help adjusting dimensions and animation in assembly

I'm getting better, just not there yet.

I have an assembly, and I need to lock the position of some parts, then allow movement of a slide.

In the Pack N Go I included a drawing with a couple questions that should help explain what I want to do.

My current Mates may be part of my problem, so I could use some help on how to adjust (fix) the assembly.

Any help is appreciated.