Navigate to the community in which you would like to manage permissions.
Click the settings cog.
Select Permissions under Community Management.
You will now see a list of any users with permissions that apply to the current community, including Global Administrators, Community Managers, and Content Editors. (Note: you cannot make changes to Global Administrators permissions within Community Management.)
Click +Add additional users.
Begin typing the user’s name and then select it from the dropdown list.
Select Community Manager or Content Editor from the permissions dropdown menu.
Click Finish.