Okay, so, there's a few things to keep in mind, and a few tips on how to get started. It might seem really daunting and intimidating, given the number of writers and the sheer scope of things, but it's really not that bad!
With the issue of time, the In Character Dates are stretched to three days. I know some prefer to keep everyone together on the same day, but with a three day window, this is to keep people active and not, say, restrained by having to wait for a GM Post or another writer. You don't have to go in order with regards to the dates, but it's strongly advised to sort of keep track of everything and not get too far ahead of yourself.
What I usually do, when getting into a group game, and it's something I've advised others who are new to it, is to begin by writing for yourself. Throw up an introduction post to your character somewhere, and use it as a sort of advertisement. Show who they are and what they are, their personality, a little preview of them. You can post it, and take the link to that post, and put it in, say the OOC or the Classified Thread, and say "Hey, this is my character. Look how awesome they are. Anyone want to write with me?" It might not be instantaneous, but it works, from past experiences. You might have to do a couple of posts, but it can definitely be worth it.
And don't be afraid to sort of check in with other writers and reach out to them to see if a particular character of theirs might be interested in working out a scene or shared history. There's a few GM NPCs as well that are around, and can be used to work in scenes or get stuff going. There's one, a tavern owner, who is sort of a middleman who can provide jobs and connect individuals if needed.
We actually have a great collection of writers who are really easy going and are fun to work with. It's not too difficult, especially now that the holidays are over, to try and find someone to write with.
When it comes to having to read up on past posts (which, I wouldn't recommend trying to read them all, since we're approaching 300 IC Posts), I'd stick to GM Events and a few recent ones, just to get an idea and feel of what's going on at the present and what might have people talking.
All of the information links, including the OOC, Game Information (and character sheets), and Classified Threads are all listed up in the very top of this thread.