Ditto.[QUOTE="Jeff, it seems like you are supposed to slid the trim onto the clips and then secure it with the stud QUOTE]
Don't "slide" the trim. Top over the clip first, then snap the lower portion in place. Tighten end fasteners last.
Once the trim is snapped onto the clips, minor end to end adjustment with a small block of wood before tightening the end clips, can be obtained.