Welcome to DM!
All the Social Groups have their own structure that distinguish them. If you want to dive in the Social Groups a good strategy is to peek in and participate a bit in all of them (or in the ones that caught your attention) and then join then ones that you like the most.
Personal suggestion: visit The Band of the Red Hand (Social Group). We need more new recruits to do all the washing. It usually goes in this order: we offer you drinks, food, music and games; you realize how awesome is the Band and decide to join; then the fun ends for you and beggins for us; you end up re