Inability to Sharing Documents to group in chat

I am 2 weeks new to Zoom Pro.  When I am in a chat and want to share a document on my MacBook Air, the documents I have saved on the desktop (or anywhere else for that matter) is not......Active or clickable.  I see the dim figure of the files (usually pdf) but I am not allowed to click and submit them.  They are inactive for some reason.  (my best description).  A little help?

Thanks