What to do?

I just registered it last night and I've been playing it for a while, and I have a question.
I'm sure I'm the only person who couldn't figure it out, but what do I do after the first boss?
Am I supposed to get some sort of upgrade? I think I've tried every possible path in the Wasteland and the ones I could in the Volcano.

Try exploring the south parts of the Volcano, but be careful because of mines.

🙂

Oh, ok, I hadn't realized that that one switch opened that one thing.