The easiest way to do this is for a network administrator to go to:
Network Admin > Sites > All Sites
Hover over the blog that you wish to add the teacher to and click “Edit”. Then click on the“Users” tab. You will then fill in either “Add existing user” if the user already exists on another blog, or “Add new user” if they are new to the school’s WordPress system.
Note that for an existing user you can simply start typing their username and the system will find the user for you. For a new user you are required to add an email address. The system will send the username and password to this email address. If you do not have an email address you can enter a dummy email. If you do so you must edit that user’s profile after you have created the user in order to manually set their password. You must then communicate this to the user.
You can also use this method to add a new pupil to a class blog. Remember, because you will be using dummy email addresses for children’s logins you must edit their profile and manually change their password after you have created the user’s login. You should also remember to add the child’s details to the class spreadsheet of user logins.
An alternative method is to use the Blog and User Creator plugin found on the Users menu.