A/C Charging with the recovery Machine?

[nissanracer300zx]

Does anyone know how to use the recovery machine, I need someone to tell me? when you have finished evacuating your a/c system and you want too charge it with the recovery machine, do you have to open both the low side and the highside too charge from the cylinder the liquid valve and the vapor valve have too be open? is that how you charge?

If you wanted too evacuate your A/C system, can you connect your manifold gauge set service hose in the back of the recovery machine and open both the low side and high side valves is that the proper way of evacuating with the recovery machine?

Or could you just use the recovery machine hoses and connect them to the low side and the high side of the cars a/c system and open both low side and high side and evacuate even if the hoses from the recovery machine are used seperately from recover and charge?