As the first step in installation, you need to find out a proper location for your air conditioning unit depending upon its size and also on the size of the room. The location should be decided in such a way that it can cool whole room, not some part. There should not be any obstacle that prevents circulation of the air.
The next important thing that you have to think over is the power point. The power of AC must be considered as the power breakers can handle the power being used.
Next you need all the tools required for the process. This includes many things like measuring tape, caulking gun, mounting hardware, waterproof caulk and pencil, foam insulation, screws, screwdriver.
Then fix the mounting brackets that you get with the air conditioning unit. Also take out the instruction manual that come along with the AC as it has all the step by step process needed to do all the connections. Make sure that you are following the guidelines correctly to avoid any chance of accident.
This will include sliding the AC unit in the window (if it is a window AC), fixing it to the mounting brackets. You must use the foam very carefully to seal the top of the unit and the window as it must not slide out. If you are done with this then just do a quick check of all the connections and then plug in to enjoy the cool breeze in your room.
These are some simple steps to install an AC unit at home but if want to install it in a big place like restaurants or offices then you must go for the technical expert to avoid any accident.