You can poke a couple holes in the cup (if it's plastic), and use wire threaded through the screen. Making sure that the ends are on the outside of the cage. I like using rare earth magnets, makes it easier to take the cup out for cleaning.
As far as what to do for your new guy, I would definitely make sure he has access to water, and throw a few feeders in the enclosure. Some chams won't eat for a few days after coming home, but the few I've had have eaten the same day they got here.
Also, try not to fuss with his enclosure any more than you have to. He'll need a little time and space to get used to his new surroundings.
