To add or remove a user as a Site Admin, you must be logged into the System Administrator account. This is the account you will have received login details for upon the creation of your intranet. If you are unable to access this account, please reach out to the Oak support team.
Log into the System Administrator account and navigate to the Actions Button > Configure. Go to Manage Users and find the user you would like to make a site admin, followed by selecting their Profile.
Here you will see a site admin toggle - enabling this will automatically add the user to the Site Administrator system group. Only the System Administrator account can view this toggle.