Expand the Usergroups menu on the left menu bar, and click Add new usergroup.
At the top of the screen, you'll see Create Usergroup Based off of Usergroup and a pulldown menu. Select Registered Users from the pulldown menu and click Go. This will clone all the permissions of a normal registered user, presetting all your group's permissions correctly. Remember to do this First, because it will undo any changes you have made.
Fill in the name of the usergroup in the Title box.
If users are supposed to be able to request to join this usergroup, set Public (Joinable) Custom Usergroups to Yes under Public Group Settings.
If members of the group and the group leader are supposed to be able to view the list of group members, go down to Usergroup Options and set Viewable on Show Groups to Yes.
NOTE: If members still cannot see their fellow group members, check that the global setting is not overriding the usergroup setting: Under vBulletin Options -> User Listing and Profile Viewing, make sure that Members List Enabled is set to Yes.
At the bottom of the page, under Default Forum Permissions, choose Registered Users from the pulldown menu.
This is to set the groups default Forum Permissions, which is distinct from the Usergroup Permissions that we preset above. See the documentation for more details.
Click Save at the bottom of the page.
You should be returned to the Usergroup Manager and see your usergroup. If your usergroup is a public or joinable group, you'll see it in the Public (Joinable) Custom Usergroups section.
To allow a group leader to approve requests to join one of these usergroups, add one or more group leaders to the group. Select Add Usergroup Leader from the pulldown menu to the right of the group once for each leader you want to add.
If you do not add a usergroup leader, anyone may join this group without approval.
