To gas your kegs of home brew beer correctly, your kegs must be cold, this is a must as the brew will not accept and asorb into the beer when hot.
It is best to have your fridge set to around 4 C.
Once that your keg is cold you can apply the Co2 gas to the keg for approx 13.5 - 14 hours on the maxium pressure the regulator will give you.
It is best to leave the keg for a period of time to allow the gas etc to settle. After charging your keg, decrease the pressure to the dispensing pressure.
You may need to refine the times given after you have sample your drop, it may need to be adjusted by 30 mins either way, depending is your brew is overcarbonated or undercarbonated.
When charging your keg on higher pressures other than pouring, always ensure that you beer line is not connected to the keg.