Make sure you have all parts ready before dismantling the gantry, rods and pulleys!  
Assembly:  Re-assemble the rods, belts and pulleys as normal without the blocks, just the brass journal bearings in place. Don't tighten the sync pulleys, but tighten the driving ones (motors).   Place blocks on the rods and assemble the key wedges, don't tighten. Slide in place the blocks over the journal bearings. slightly tighten the bolt.  One block at a time:  Place the square nut in its captive location.  Screw the bolt few threads through the square nut.  Slide the banana in place.  Capture the belt under the hinge screws passing through the tube cuts acting as rollers.  Position the gantry and secure rods on the blocks using the brackets. Gently tighten bolts.  Tighten the belts using the adjusting bolts, enough to remove slack and hear the belt give a tone. You can balance all belts to give the same tone. Don't over-tighten!  Square the gantry and tighten the pulleys. You may want to use a thread locking compound like Loctite Blue. Remember that to untighten later, you will have to heat the grubscrews or use acetone to dissolve the thread lock.  
Level the platform and star printing.  
Enjoy!