The episode is titled "Archie and his New Pals" (plural), but only one new character is introduced - Sabrina. (two, if you count her cat, Salem)
The point of the episode is to bring Sabrina into the Archie show, but apart from brief exchanges with Miss Grundy, Mr Weatherbee, Dilton, and Big Moose, Sabrina spends the entire episode lurking in the background. Neither Archie, Jughead, Reggie, Betty, nor Veronica ever meet her or speak to her.