Anyone know more about this subject i know its something to deal with Transfering the maps from HL2 to the portal file but im trying to figure out if there is anything else i need to do

I didn't know you could do that :S
Do you want it in Garry's mod?

yeah if you youtube portal gun in halflife 2 it should come up and how do you get it in Garrys mod? maybe thats what the guy in the video was doing.