Air conditioner hose fittings are metal hose collars that attach a high-pressure rubber hose to an AC coolant pipe. These connections need to be perfectly formed to hold in the coolant that circulates inside of every air conditioner. Any imperfection during the crimping process will allow coolant leakage, and essentially render your car's AC unit useless. The only way to make a perfect crimp is to use a professional crimping tool, and while they are not inexpensive, there is no other alternative.
Slide the hose fitting onto the end of the hose, then push the hose onto the AC copper pipe that needs to be connected.
Match up the correct die with the hose fitting, and place it inside of the crimping tool's jaws.
Place the crimping tool over the hose fitting and squeeze the handle. The hydraulic action and the correct die, will crimp the hose fitting tightly, and will make a perfect seal between fitting and hose.
