how do i install freon?

Google "air conditioning recharging" there are several Youtube videos to watch which are quite good, but if the system has a leak the leak needs to be repaired or the refrigerant will soon leak out again.

BLUE IS COLD LOW PRESSURE THATS THE SIDE...NEVER TOUCH THE RED HIGH PRESSURE SIDE, IF YOU DO NOT KNOW WHAT YOU'RE DOING YOU COULD SUFFER INJURY OR DEATH THIS IS A DEADLY GAS EXCHANGE AND YOU NEED THE PROPER TEST FITTINGS TO DETERMINE THE CHARGE PRESSURE BE FORE YOU RECHARGE AND RISK BLOWING EVERY THING UP...RECHARGING KITS HAVE A GAGE AND FITTINGS AND IF YOU CAN READ YOU CAN TEST THE COLD LINE FOR IDLE PRESSURE, THEN ADD NEW GAS! BE CAREFUL...GOOD LUCK!