OG User Roles: Usage

USAGE

When you assign a group user to a role, the user will have the permissions granted by that role as long as he is within the group context.

To assign a group user to a group role:

As a group manager or administrator, go to the Group Home Page. In the
group navigation menu you should see an link titled:

"# subscribers".

Click on this link. You should next see a menu tab which says:

"Configure member roles"

Click on this tab. You should next see the list of subscribers for this
group. Next to each subscriber should be a list of the assignable
roles you selected in "SETTINGS" step above.

Check on each role that each user in the group should have, then don't
forget to click on the "Save Changes" button at the bottom of the page.

Each user will now have the privileges of the role(s) you have checked
for him while he is within the context of this group.

Using Content Access and ACL with OG User Roles: http://groups.drupal.org/node/5392