Hi, Welcome Aboard!
I haven't looked at L4W, but I can pretty much guess "Eh, the same."

The
first post of this thread points you to where you can build your character sheet on the wiki we have over at
http://livingpf.wikia.com/wiki/Living_Pathfinder_RPG_Wiki. Once you have a character built, you ask for it to be reviewed and approved. Two people need to approve first level characters, one of them being on of the judges. Then you go to the "tavern" known as the
Dunn Wright Inn and start conversing with the other players waiting around for work to do. Eventually, (yeah, a few weeks maybe) a GM will send an NPC into the DWI to recruit several brave folk for a new adventure. A new game is forming right now and is looking for a couple more players.
If you want the more philosophical answer, it is a living world where we strive to keep the story lines, map, history and magic item availability in the magic shop in a consistent, organized living campaign. We use the CRB, APG, UM, UC, AA, UE and ARG books, but without using Golorian specific names/deities/places.
The most detailed information is in the first post of this thread. The thread has evolved over time from "This is a list of adventures" to "Hello Newbies, Start Here!". I recently added to the OP and hope I have covered all the basic questions. Any questions, just ask. We are helpful. Do get a feel for the flavor, simply read about the last two dozen pages of the DWI thread.