Only stuff found in the core rulebook is available for use.
Foundry VTT will be available for characters. MapTool will be used for the table display.
Every player will need to create a region for the world. I suggest reading through pages 4-9 of Perilous Wilds for ideas and examples. A region can be anything, floating islands in the sky, underground city, chain of islands in the ocean, the shire, a city on the back of a behemoth, whatever. You can create as much or as little as you want after you make the minimum needed.