1. Click the Organization tab at the top. Go to Admin > Admin Users
2. Click Add in the upper right
3. Select what type of Admin they are (Full Admin or Season/Group Admin) and fill in the rest of their details. Once complete, press 'Add'.
Once you press Add, an email invite will be sent out to the league admin.
More on Full Admins and Season Admins:
A Full Admin has access to all functions in the account, including registration, website, teams, members, email, etc. They also have the ability to add additional league admins.
A Season/Group Admin has access to selected material. This can be specific divisions in your account or specific seasons. Season/Group Admins have limited functionality, including no website editing permissions and assigning members to teams after registration (but no ability to edit the registration form itself).
For more information on group admins vs full admins, click here.
Once you have added the admin, you will see all admins listed in the Admin > Admin Users section. The user you have added will also receive an email that they have been added as a league admin with instructions for how to set their password and access their account.