You have the mount T's, use a 3-D sketch in space for use in creating extrudes.
Roll back the feature tree, show the planes and sketches and 3-D sketch to understand the process. Hope that helps; just continue using the same process, and use 'feature scope' selections.
See downloadable example: https://www.dropbox.com/s/a8n9p79zeq...nt.SLDPRT?dl=0
-Christian