Thank you for the reply. I followed the link above but it still does not work. I have both the checkboxes checked on the properties page, but I still cannot select the requirements at the test script level after I click "Edit Test Script" in the second column on the test script table. Why is it not working?
Thanks

you can only add requirement to script level in the test script not test script view's 'Validate requirement' column. Following the documents, if test script is a part of a test case which is linking to the requirement(s), you are able to add the requirement(s) to the script step, something like:

In Test Script view, you can see the link and filter, not to add another link from there.
Hopefully this clarifies.