Increased the size of the flex duct to front bedroom to 9”. Added a 12x8x9 bucket and grille. Ran the 4” flex that was wyed to the supply plenum. Added a new 9” flex duct with new bucket and grille to the master bedroom. Ran the existing 6” and 9” ducts to the supply plenum. Built and installed a new return plenum with media cabinet inside. Sealed all connections with mastic and hardcast. Testing heating and cooling operation.