Why can't I add Keywords?

No.14416138 ViewReplyOriginalReport
I'm using Mendeley, and I've been told to add keywords to these files. In internet tutorials I've seen, the option to add keywords is usually found after tags. However, the option doesn't seem to be there. Thanks in advance.

The program is Mendeley Reference Manager
2.69.0
© 2022 Mendeley Ltd. All rights reserved.