In MAGIC, all versions of the guideline have its own separate ID, and also permissions-list. That means you can give Admins, Authors, Reviewers and Viewers access to only certain guideline versions.
If you want to grant someone permissions to the current draft, you need to access the permissions list in the draft and add them.
Once a user is included in the permissions list of a draft, they will be in that list in all subsequent versions, until they are manually removed.
If they are added to the current most recent published version, they will not have access to the draft, and not to subsequent versions.
To add authors, admins and reviewers to a guideline, go to the guideline settings (gear icon), and to the permissions tab.
To note: The person you are adding must have a MAGICapp username.