In order to prepare a new compressor for installation you will need to prime it. If you do not prime the compressor properly you could seriously damage it, and void the warranty on the product. Priming a compressor consists of adding oil to both the receiver dryer and the suction port of the compressor. Before starting you will need to know the oil capacity for your system and your compressor. You can check here to get the system specs for your specific vehicle.
Once you have determined the proper amount of lubricant for your particular compressor, pour half of the amount specified into the suction port of the compressor, and the other half of the specified amount into the receiver dryer.
Once you have installed the compressor back onto your car you will need rotate the compressor clutch 10-20 times to insure that the oil is properly distributed throughout the system and the compressor. To do this you will need a spanner wrench.
Do not turn the compressor nut in the middle of the pulley as this may affect the air clearance between the clutch pulley and the clutch face plate. After you have rotated the pulley 10 to 20 complete revolutions, the compressor will be properly primed.