To collaborate on a course or a section with another instructor or TA, click the "Collaborate" button on your course dashboard, add the TA's or instructor's email, select their access level, then click "Invite".
The instructor will receive an email notifying them that they've been added to your course.
'Can View' vs. 'Can Edit' vs. 'Can Admin'
With 'viewing' rights, the collaborator will have the ability to view the course and the assessment results, but will not be able to add or edit assessments, download or upload test sheets.
With 'editing' rights, the collaborator will be able to add and edit assessments and print and download test sheets.
With 'admin' rights, they will have all the same abilities as an 'editor', but will also be able to add/remove collaborators and sync the grades to Blackboard.