I use a bookmark and place it on the Bookmarks Taskbar.

I don't think Firefox allows web pages (http: or https: address) to link to about: pages or file: pages. (file: address can link to file: but not about:)

If this is for personal use, FredMcD's suggestion may work best.

If this is for general public use, I think you'll have to provide instructions or an illustration instead.

FredMcD said

I use a bookmark and place it on the Bookmarks Taskbar.

Thanks. That works for me.

Glad to help. Safe Surfing.

There is an Options/Preferences toolbar button (cogwheel) available in the Customize palette to open the about:preferences page. There is also the about:about page with a list of all available about pages.