I've only dabbled in it so far.
Poisonous planet with toxic storms occurring every time you blink, so be careful.
I'm going to have to hoof it far away from my ship to get to a location where I can build a base, the planet seems crowded, as all players doing this expedition are on the same planet, however I need the blueprint for the base computer first.
I haven't spent enough time to actually look at all the steps to get the blueprint, so I suppose the thing for me to do next is sit in my ship, and go over all the different tech trees.
I may be too impatient of a person to actually do an expedition, we'll see.
You get two months, and you don't have to complete things in order. I scanned all the creatures on the planet, and got a reward from tier 3, even though I've not completed tier 1 yet. So you're free to basically do the expedition any way you like, which is cool.
One thing though - apparently one of the rewards you get is a Station Override, which you can put into the terminals at the back of stations. If you've not completed the expedition though, it'll say you're unauthorised & then swallow it.