Sign in to your Tumbler account, and then click the down arrow next to the name of your primary blog. Select the name of your secondary blog from the list, and then click “Members.” Type the email address of the person you want to add, and then click the “Invite to this blog” button. Click the “Promote to admin” button next to the name of the person you want to add as a co-admin. Click the “Promote user to group admin” button to confirm that you want to permanently allow the user to administer the selected secondary blog.
