If you have a gauge manifold set, hook the vacuum pump to the center or yellow hose. Hook the low side hose, blue, to the low side. hook the high side hose, red, to the high side. OPEN BOTH valves a turn or two and start the vacuum pump.
When done evacuating, CLOSE BOTH VALVES FIRST before stopping the vacuum pump.
You charge through the LOW SIDE ONLY. you hook your refrigerant source now to the yellow line and use the low side manifold valve to ADD refrigerant. This allows you to "fine tune " the amount that you put in while checking your pressures.
Look under the hood, generally on the radiator support and It will tell you how many pounds your particular car takes.
Chris

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My Truck.. 2007 DODGE, 5.9 Cummins, 6spd stick, 4X4. My car..1977 240D, OTHER WHEELS...1955 VW Oval window bug, European Delivery (Holland) with a 1700cc, 2 barrel, Porsche drum brakes. 1939 WILLYS Pick-up. 1967 Triumph 200cc Tiger Cub. 1976 Honda 550F 4cyl Motor Cycle.