So, got a kegging system for Christmas. Keg came pressurized, so I know it can hold pressure. However, I just got my CO2 tank filled, and I'm trying to seal up the lid and put a few psi on the keg again. Can't do it. CO2 is leaking all around the lid that I can see when I spritz soapy water on it. Is there some trick to this? Can you post a step-by-step for an idiot like me?