I completed that game - built the ship, staved off a number of attacks over the 15 days it took the power generator to spool up, and launched my colonists homeward.

I decided to start a new game, so I'll write it up as I go.
You start by picking your scenario - I'm going with "Crashlanded."



Then your "storyteller" - the AI that controls random events for your colony. You can change any aspect of this at any time during the game. There are also mods (Rimworld is HEAVILY moddable) which create new storytellers.
I'm picking Phoebe, which will be a new one for me. I've been sticking with Cassandra. Phoebe is a little more intense but at greater intervals between events. Supposedly.



Once your world is generated, you choose your landing spot (or pick random). I'm still new to the game, so I'm picking a temperate forest to keep things a little easier.



Finally, you pick 3 out of a given 8 colonists. They each have different stats in terms of abilities/tasks they can accomplish as well as quirks - both positive and negative.







There is a mod called "Prepare Carefully" which lets you tweak any of the colonists as you would like. I didn't use it for any stats on the colonists I wound up choosing, but I did alter their appearances.