Step 1: Run timing belt thru profile. (Not shown)
Step 2: Take off top of T45 reverse unit. (Not shown)
Step 3: Run timing belt thru bottom of reverse unit & feed it around the pulley. (Not shown)
Step 4: Put top of T45 reverse unit back on. (Not shown)
Animation begins here
Step 5: Bring upper Power-Lock on 45x90 rail into gap on front of reverse unit.
Step 6: Slide reverse unit down until it is flush with bottom of 45x90 rail.
Step 7: Tighten upper & lower Power-Lock to secure reverse unit to rail.