Unlike a Forum Administrator who can access the both the back-end administration panels and has full access to all options on the front-end a Forum Moderator has no access to the back-end forum administration panels and you can set which front-end options they are allowed access to or abilities.
Upon installation Simple:Press creates a default Usergroup for moderators of the forum Any member can be assigned as a forum moderator simply by adding them to the moderator group. Once added to the Moderator User Group the moderator permissions can be set in the Manager Permission Sets panel. In this panel you can set what abilities the moderators have.
After setting the moderator permissions each forum must have the moderator permission set or added to each one that will be assigned to the moderator. This gives you the ability to have moderators for individual forums or all as may be needed.