There's an Enertron, a save point, and a Shop up on the top floor of Arris Dome with the humans. You must descend to try to find the food below. In a bit of a reversal of expectations, the first fight you'll have is against the Boss, the Guardian. This fight follows a pattern that will become familiar throughout the game: you must take out its helpers, and keep doing so whenever they are revived.
Once past the Guardian, get the Seed and examine the dead man again to find out the secret of the rat on the rafters. Chase the rat down to get the password to open the other side of the facility. You may want to rest and save before moving on. You can avoid most of the fights on your way to the info center, if you want.