Yes, while scanning the bank which contains the system that you want to enter TG's for; press <MAN> to stop the scan, the radio should stop on the control channel. (It is possible for it not to do so, but that would depend on what else you have programmed into the frequency bank.)
After doing the above, press <FUNC> then <TRUNK>. This puts the radio in Trunking ID mode. There you can enter Talkgroup ID's and alpha tags for the TG's. If you get a message like "Not trunked! Press mode" you have not programmed the frequency bank correctly.