Paths are extras you can gain along the way. As you meet people in these groups you may desire, or be invited, to join. You gain special abilities, knowledge and access to what ever the group is about. The most common is the AG (Adventurer's guild).
I also welcome ideas and work in this area if you have a special group in mind.
You must meet the requirements. You can meet them at the same time you join or advance in a group.
Groups sometimes cost money or XP to join. The money can usually be negotiated when needed. The XP cost however must be paid in full. You must have enough XP that paying the required XP so that it will not reduce you to the next level. All other Requirements for paths will be explained in the path.
Racial Paths require a commitment usually at character creation. Sometimes though they can be introduced as a 'Reveal' in game, but the DM has to approve this.