How did Gnaw and Cindersaur become members of the Predacons and Terrorcons, respectively?
In the case of the former, it was more by accident than anything. Gnaw had been the leader of a team of Sharkticons sent into the depths of Cybertron to pull the large switch controlling the Exponential Null Generator. When that plan went awry, he ended up following Galvatron to the surface, and from there to Chaar, without being noticed.
When Galvatron finally stumbled across Gnaw (chewing on the base of his makeshift throne), the Decepticon leader threw him to the Predacons—declaring that since they were both spawn of the Quintessons, they should get along fine.
Razorclaw knew better than to argue with Galvatron when he was in one of his moods, and reluctantly accepted the Sharkticon. When the Predacons went on their hunts, they would toss the scraps to Gnaw, keeping him around as a living waste disposal machine.
Cindersaur, by contrast, was deliberately headhunted. Hun-Gurr had been keeping his watchful eyes on the Combiner Wars, and had seen the other combiner teams picking up new members to replace fallen ones or to increase their number. The Terrorcons' rivals, the Technobots, had acquired two new members even, which stirred envy in the Terrorcon leader. Still, Hun-Gurr was not about to recruit just anyone to join his squad; he wanted an outcast—someone whose loyalty would lie with him over any other Decepticon. He found the perfect bot with Cindersaur. The Firecons had recently broken up, and Cindersaur had found themself lost without their teammates... literally. They had gone on a rampage, ending up completely disoriented in Chaar’s wilderness. Their usual means of retracing their steps, by blazing a trail behind them, had completely failed them in a landscape where everything was already burned and blackened, and they'd been wandering in circles for months.
Hun-Gurr tracked them down, and offered Cindersaur a place in the Terrorcons. He had a quick recruitment form for Cindersaur to incinerate, and that was that! The other Terrorcons were hesitant at first, but they soon came around, after realizing that the smell of smoldering metal helped mask Blot’s stench.
