1. It needs to be on the same file, otherwise you cannot do it inside finale.
2. Just go to 'page tool' and move the systems accordingly... There's nothing to it.
3. Add the title, work, etc, on the proper place.
4. Make sure you change the measure numbers, cause you might end up on variation 2 with measure number of 69 and that would be ugly. You need to go to the measure tool and go to the menu and click on 'change measure number regions' (I think. I don't have Finale on this computer so I cannot check). Then choose the first one and make it stop at the last number of the 1st movement (otherwise when you add a new region you'll have two numbers on each measure). Then add a new region for the new part/movement.