To add your TA to old CourseWorks, log in to your course site, click on “settings” → “set members”. Then type your TA’s UNI into the space and select “TA” from the pull down list. After you confirm the addition he/she should be able to access the site.
If you want to restrict or expand a TA’s (or other site member’s) settings, click on “settings” → “set members” → “show student panel”. There you should see settings to allow TAs (and others) special access/editing privileges within CourseWorks.
Note, if you would like to add a TA (Teaching Assistant) to New CourseWorks, instructions are available from the below article.