Welcome to WikiTree! Although you may be here under less than ideal circumstances, we're glad you are here. Please make yourselves at home. WikiTree is for everybody, so let me show you around. (Please excuse the mess. We weren't expecting quite so much company quite so soon.)
As you can see, the place is a little over ten years old. The foundations are sound, but it looks like we're going to need to add on some extra rooms, so please pardon the noise and sawdust. We'll try to have you all settled and comfortable just as quickly as we can.
This room over here, marked "Get Started", is for you. Feel free to make your own profile, and fix it up any way you like. (Although, just between you and me, some people get a little tetchy when they find out that somebody has used a picture that's not actually them, so I'd recommend using photos of yourself, rather than Marilyn Monroe or George Clooney, okay?)
Once you've settled in, I'd recommend reading through, and then signing, the Honor Code. It's not like we don't think you're trustworthy, but it just helps to reassure people that you plan to play nice with the other kids, and that you're not going to go around kicking down anybody else's sand castle.
After that, the next stop is adding in all of your family members, with all the information you can remember about them. In fact, now might make a real good time to call up your family members and confirm a few things, like birthdates, anniversaries, and such. I'm thinking that they're probably going stir crazy right about now anyway, and would probably be even happier than usual to hear from you.
Once you've got your family tree built out just as far as you can manage, the next thing is to check sources, and see how much farther they'll take you. There are a bunch of links in the "Genealogy Help" category, listing sources for records like birth, marriage, and death registries, census records, graves, military records, and other ways to find information about your ancestors. (Yes, it might kind of seem like snooping, but it's our way to honour those who, however distantly, were responsible for bringing us into this world.) Ideally, you'll eventually bump into some ancestors who already have profiles here on WikiTree. The good news is that finding your third or fourth grandparents might lead you to finding some distant cousins you didn't know about. (That has happened to me.) The bad news is that you may find out that you're related to somebody you'd prefer not to be, but you can't have everything.
Once you're all written up, signed up, and connected up, there are still a whole bunch of things around here to do. If you can imagine something, family tree-wise, there's probably a project for it. So feel free to look around, and sign up to take part in whatever tickles your fancy.
And again, welcome.