Colony ships whiz this way and that. Here, for instance, is Teani-3, a beautifully habitable (if short-yeared) planet in orbit around a small yellow star.

Teani-3 has natives! The natives are... weird. For one thing they're telepathic, which is incredibly cool and all the greens are SO excited. You'd think this would make communication easier, but it kind of doesn't, because they are also weird in other ways. They have several traits which no one can figure out in terms of evolutionary stability - they can't actually approach each other's homes, which seems like it would collapse as soon as one managed to mutate to be otherwise, even presuming they must have reproduction figured out in some fashion. Initial attempts at one-at-a-time peaceful introductions are met with violence, and some of the greys die, but Tapa has warp now and doesn't have to just let aliens commit some murders so they can beg to be let off their rock; the violent aliens die. The less violent natives don't get killed. That ought to improve the gene pool a bit.

The natives can't approach Amentan territory either, once they've got it. Enough adjacent violent ones, enough native-unclaimed land (perfectly good land of the sort they seem to like, even, fancy that, what is with this species), and they have a big blob they can mark with a locally legible perimeter, and they have room for a city and farms. There's a secondary local species that seems just shy of being full-on people, also telepathic plus those can go in cities, but they're little birds. Some Amentans like them a lot, actually, and start trying to convince them to be pets (it is provisionally illegal to insist on it).

Figuring out how to talk to the aliens is hard; they only broadcast and can't receive. The greens are SO excited, though. They will try Very Hard to figure it out. Here is an anthropologist turned xenologer whose botanist husband is safe back in the city with their baby, hiking out with a grey escort to meet an alien.