For best results drain the fuel from the ring tanks before launch. The boosters have enough thrust to easily get the KDX Enterprise to a 120x120 orbit, which makes it easy to refuel it from an orbiting tanker station... or you can just transfer fuel from the booster(s) to the rings... or you can just strut the buhjeebuz out of it and launch it all up!
Action groups are listed in the craft description.