Upon first entering Softport make your way to the south of town where the docks are. Terry is standing here and sells tickets to Fenris Port.
The building just to the northeast of Terry is the inn. It's run by a common innkeeper with nothing of note to say. Go into the hallway and enter the first room to the north. Tucker is standing in the corner, and he's one of the four Avernites sent to the surface before you. Talk to him about what he's found, and pay attention to what he has to say. When he's done talk to him again and ask him if he's going to return to Avernum. Doing this will get you 25 experience.
The building just across from the inn is actually two barracks.
To the east of the barracks is a common fletcher, and just north of that is a common tailor.
To the northwest of the barracks is Mayor Scowcroft's office. The mayor will give you a quest to find Zik, who can be found in Dorngas. He'll also tell you to take any items you find on his bookshelves. There's a couple scrolls and a healing potion there for you to pick up if you want them.
The room to the south of the Mayor's office is a common armorsmith, and across from it is a temple for the Church of the Divine Lucre. It's run by Nydia, who provides healing. More importantly, this is who Commander Corrie told you to ask about the Ritual of Sanctification. Nydia will send you to the north end of the mountains to the north, to a Hermit's Hut, so now we're off to see the Hermit.