How do i add a PDF to my site for download?

Evening folks,

I would like to add a downloadable PDF to a page on my site. I have added it via Media all ok and attempted to insert it into the page.

I learned that I need to select File URL for this one but when I test it, it isnt working.
The link opens a new tab but the PDF isnt avail at all.

My site is a multisite with the domains mapped via an A record set up, (if that makes a difference at all?) The link doesnt show up as it appears as the subdomain as shown here:

Appreciate your help if you can.

Richard C