Attached are 2 PDF's.  The first (Frame question) shows my current SW part.  I'm trying to add 2 support Structural Members (2x2).  The other PDF (Frame Reference) shows what I'm trying to achieve.

Part of the problem I'm having is getting the bottom side of the new support piece to start at the bottom of the existing vertical frame piece, and getting the bottom side of the new support piece to end at the outer-most edge of the existing horizontal frame piece.  I'm having some "Trim" issues as well.

I'm very new, and am trying to figure out the best way to achieve this... From the start (Planes, sketches, etc.)

Any input would be appreciated.