@filipd1 To manage pupil permissions you're probably best using policy packages, which are in the Teams admin centre Policy packages - Microsoft Teams admin center
There should already be some Education policy packages listed there which you can edit and assign to pupils. To assign them, click on Group package assignment, pick the package (e.g. Education (Primary school student), then pick the group you want to give the permissions to.
While there's no specific option to prevent people creating Teams, you can stop people from creating Office 365 Groups (which are required for Teams to function). If a user does not have permission to create groups, the "Create Team" pages also disappear from their view. This is a bit more involved and requires PowerShell. - details of how to do this can be found here: https://docs.microsoft.com/en-gb/microsoft-365/solutions/manage-creation-of-groups
