"x100" represents the number of seats available for this subscription.
This will then take you to a screen where you can manage various aspects of your subscription.
The top link allows you to edit your profile – here you can add details including the name of your Educational Institute, the type of institute it is and the country in which it's based. You can also add the rough size of the institute and contact details including a dedicated point of contact and the website.
The second section of the subscription page shows you any projects that have been shared with you via students. Education users gain an extra option in the main menu – the ability to share their project with an admin. This stores that project in this section of your subscription so you can access students' work more easily.
The third section of the subscription page is where you can assign licenses directly to accounts. Click "Manage your licenses" to bring up a list of your seats, including their associated username if you’ve assigned any seats. You can click "Edit" to make changes to a seat.
Here, you can assign a license to a user by typing their username into the box or you can remove a seat from your subscription entirely. Please note if you're using licenses that have been given for free, this link will not work.
If at any point you want to unassign a seat that is already assigned to a user, go into its details and click "REVOKE".