Countdown timer not shared for shared web pages.

I use  Zoom Workplace 6.2.7.  I typically share documents and material from web pages via the Zoom session.  I would like to imbed a simple countdown timer for all attendees so we can move forward more quickly through the material.

The Zoom timer tool does not appear on participants' screens when I share either a web page or a static document.

I fear I've overlooked something trivial here but I can't find any relief online and would appreciate any help. Thanks.