I need to install refrigerant and do not know hoe.

If you do not know what you are doing I would suggest taking the vehicle to a mechanic that is certified to perform the repair. If you need to add refrigerant then there is a reason it is low. The leak needs to be found and the system needs to be sucked empty so it can be opened up and repaired. Then it needs refilled and topped of with the correct amount. I have seen it more than once that a customer will add too much freon to a system and do damage to a very expensive compressor. Sometimes a cheap fix is very expensive in the long run.