For the purposes of this introduction, I am going to assume that you have already signed up. If you encounter any sort of problems to that effect, let me start off with a few general notes.
If you ever have a question about a page, and how it works, press the question mark in the corner of the page. There, you will be able to dive into the Imperium's oversized help section. Every page you visit on the Imperium is documented there, as well as many others. At any time, in any help page, you can click that same question mark again to go to the main index of help pages.
If you encounter something you know is definately wrong, or misbehaving, at the bottom of each page, in the footer, there is a "Found a bug?" link. Click on it, and fill out the form (if you need to, look at the help page). One of the Ministers will address it as soon as they can.
Now. Welcome to the Imperium, a grand town of beasts. It can be a little overwhelming at first (and if it isn't, you haven't gotten to the half of it yet), but eventually you will be used to it, and it will make complete sense. It should make complete sense anyway, but we prepare for eventualities, here.
You're in this Imperium, and, upon signing up, you're put into a ship. You are, of course, the lowest of low ranks. There's a lot of ways to make money in the Imperium, and being in the Navy is just one of them. However, when you're just starting out, it's the best one to follow. Being on a ship brings you close to a group of other beasts, and affords you benefits like a pension, and clear path up.
First thing you should do is zip on over to "Change User Information". Fill in what you want (as well as your password - you need to put that in for anything to change). Have an interesting description, and a good history - a good thing to mention is how you came to the Imperium. Were you a longstanding citizen, or an immigrant? Why did you come? For the money, or for the wonderful city life?
Next, go on over to the ship's mess, and say hello to your fellow shipmates - you'll be spending half the time in the club on a ship with them, so you should be nice. Acting kindly, and not annoying, will endear you to them. Try searching the help pages before asking questions about how things work on the boards.
Once you've said hello at the mess, you should also go over and say hi at the Bilge, the local pub/message board. Be respectful there, too - in fact, it's really a good idea to be nice and respectful everywhere.
Now to get down to spending that starting 100G