Here are some important pieces of information if you're interested in joining us to participate in Paizo's Global Organised Play Campaign.

Joining the Pathfinder / Starfinder Society
1. Visit Paizo's website at www.paizo.com  
2. Go to the Organized Play page. 
3. Click the link in the blue bar that reads: "New Players Create an Account". Register an account. (You'll need an email address to complete this step.)
4. You will be given a Pathfinder Society ID. Make a note of this number, or download and print your membership card for easy reference. (It’s the same number for Starfinder or Pathfinder Society characters.)
5. Congratulate yourself on an excellent life choice.

Pathfinder 1st edition

The Pathfinder 1st edition Society Roleplaying Guild Guide is our campaign bible for Pathfinder Original campaign. You can download it FREE from this webpage .
The Additional Resources page lists all of the legal and illegal content in the original Pathfinder Society campaign. If you're making a new character, buying gear, picking feats or spells or practically anything else you can think of, give the page a quick check to make sure your choices can be used in the campaign.  Additional Resources list.
If any of these rules aren't crystal clear you might find answers in the Campaign Clarification document online. Campaign Clarification.

Pathfinder 2nd edition

The Pathfinder 2nd Edition campaign Guild Guide can be found online here .

Starfinder

The Starfinder Society Guild Guide, can be found from on the Organized Play website with instructions how to build a character and how to join a faction, gain faction benefits and choose a starship.
You can find many of your questions answers on the FAQs resource page here.