I left the town for the first time, after finishing the tutorial mission and battle.

1.  So - one way I go, I find a cave.  In there is some rotgut worm (something like that) blobs.  I attack them and they explode into 10 or more purple monsters that each have 26 or so hit points.   Instant death.  No chance to survive.  All four characters dead.

So, I go another way.   I find a huge fly monster.  Instant death.  No chance to survive.  All four characters dead.

This is THE FIRST MISSION after leaving the town.  What the heck am I supposed to do?  How do I play this game?

2.  Also - I'm not sure I understand the dual class thing.  Does the combination of the two classes dictate what skills and passives you have access to?  Is that what the classes do?  And, if I only gain experience in my main class, what is the use of the secondary class?

I'm sure there is a wonderful game in here, but it's not explained very well AT ALL, and I have no chance to survive in just the very first time leaving the town.  Am I supposed to get a mission, or do I just leave the town and explore?  I thought this game was mission based, but I didn't get any mission, other than the guy that wants me to find some ore.

Thank you very much in advance for any help getting going in this very confusing game.

It's not mission based really, that's just the tutorial. Not everything in the first area is beaten easily. The fly is basically the first boss, and you can easily go around it. The Rotworms are very tough early on as well in numbers. I suggest doing a few runs through the first area awhile before trying to tackle the boss. And make sure to save often. Especially since the game still has some crash issues.

As for the classes, how it works is you can use the secondary classes skills, but you have the attribute bonuses and gain xp to your primary class only. Passives can be used by any character in any class once unlocked.

Thank you, Zilrax.   I still think it's kind of a weird design decision to put monsters two rooms away from the city in the very first zone that can kill each of my dudes in two hits, with me having absolutely no way to beat them.  

Ok, back to the game, and skipping the hard stuff until I level up.  :o)