Well, step one is to read the Rule #1 topic at the top of the forum.
I'd recommend you start fresh once you understand the workflow. It's actually pretty easy and quick to redraw a model.
In any case, since the cover is asymmetric, a surface loft with rails will work.
- Start a sketch in a new component using the right hand face of body 9. Project the outer edges of that face to the sketch. Remove the center section so there separate left and right sides .
- Start another sketch using the bottom face of body 7. Project the outer edges of that face to the sketch.
- Surface workspace loft between the geometry in step 1 as the profiles and the geometry in step 2 as the rail.

Your sketches should look like this:

Notes:
Always fix yellow warnings and red errors in the Timeline before continuing. These will often lead to failures later in the design which may be very difficult to find and fix.
Try to avoid Moves. They are not parametric which means the move won't be updated when other changes are made. Each and every move needs to be recalculated any time a change is made in the file. This can lead to a very sluggish Fusion.
ETFrench
