"Well, it's not much different ... " Fred launched into a fifteen minute ramble, then, that proved it was actually quite different, not being connected to the system it took a new spell and a certain way of throwing the powder in to get where you needed to go, especially without being seen by anyone when you crossed into a floo that was being monitored. It was a tricky bit of magic to take yourself off and still have the floo work.
When he stepped back after the confusing, circular sort of explanation he'd given, he pushed the bag of powder into Roger's hand. "Okay, you try, and then come back."