If you already have a personal Soundtrap account and want to join an Educational account, you have to get either a code or a link from your teacher (or the owner of the account).
Once you got either one go through these steps if you have an Invite Code.
To see article on how to join by link CLICK HERE
(Teacher/Owner finds code through Edu Admin panel - Import Users - Copy code)
Join with Invite Code
1.) Log in to your Soundtrap account
2.) On your profile page click on Soundtrap for Education
3.) Click on Join With Invite Code
4.) Paste the Invite Code in the field and click Ok
5.) Confirm to join the Edu account.
6.) Welcome to your group/class!