1. The home page The home page should give you an idea of how Quantum Threat is starting, in addition to miscellaneous info about the setting. the Wiki also has more info.
2. Create your character Characters form the core of every campaign, so take a few minutes to describe the character you are playing. A quick tip: The "+" icon in the top right of every section is how to add a new item, whether it's a new character or adventure log post, or anything else.
3. The Adventure Log is where you list the sessions and adventures your party has been on. The set up for the story can be found on the Home Page, but after each future session, one of the players should create a new post detailing that night's adventures. The point of view can be anything, and whoever writes the post can take creative license.