MyBB Community Forums

Can someone explain me how can I create groups for users and than add them?

Under the "Users and Groups" section of the acp there's a page called "Manage Groups". You can create new usergroups from there, and then move your users into that group by searching for the users you wish to move to the group, clicking edit and changing the users primary usergroup.

Read this tutorial about working with usergroups.

regards