We actually have kits that are already pout together that has everything you need.
For a black unit, you can use the Advent Air RV Air Conditioner System - Manual - 13,500 Btu # ADV44FR, or for a white unit we have the Advent Air RV Air Conditioner System - Single Zone # ADV94FR.
Each kit has everything you need for a full install to include a wall-mounted thermostat, an air distribution box, as well as the mounting bracket/hardware for the unit itself. view full answer...