You need to design and select the walls for installing the ducts. Then drill holes according to size and numbers on ducts you want to install in the walls. The ducts should be insulated to avoid energy loss when passing it to registers. One register will be enough to run the HVAC ducts efficiently. Then you will link the register directly to the central unit. Direct linkage helps in better performance of the register. After that, do a test run to ensure the HVAC runs smoothly, then cover the wall. Wall drying should not worry you because the wall will automatically dry within a few days.