To assign a role as an administrator to someone, they must be a registered play-cricket user (with their own username and password) and be a member of the site that they are to administer (i.e. that username is in the database for that site under Site Administration>Day to Day>Members>Member Database). You cannot assign admin roles to a 'temporary' member, marked with an *, which has been created by a site administrator.
Once they have done this, then go to Admin>Site Management>Members>Member Database and search for the member. Click on the ‘roles’ icon (the ‘hat’) next to that entry in the database. Change the appropriate dropdown to ‘Activate’ (main admin also has all the other admin roles embedded in it, so if using that then there is no need to give the others), and click the Save button. This sets the status of the role to Pending, which means that it is awaiting action by the person to whom the admin role has been granted.
The next step must be performed by the new admin themselves; they need to go to your site and login. In the dropdown by their name at top right they will see the Administration option. They must click on this and accept the terms and conditions that are then displayed in order to activate their role as an administrator, and gain access to the admin functions of the site