Uou do not have to be a member of a club to participate.  Many clubs and communities form their own teams and prefer their teams be made up of club or community players but APPL does not require you to be a member of a club or a community to participate.  Anyone can form a team if they can meet the requirements such as securing a venue for their home matches, having enough players, etc.  The Casa Grande Region does have some additional conditions stemming from having all their matches played at Dave White Park.  See the Casa Grande specific FAQs for more detail.