To join a usergroup click the usergroup link on the page header (dependent on template design) and you can then view all usergroups. Not all groups are open access -- some are closed and some may even have hidden memberships. If the board is open then you can request to join it by clicking the appropriate button. The user group moderator will need to approve your request; they may ask why you want to join the group. Please do not pester a group moderator if they turn your request down -- they will have their reasons.