Fido does not currently offer any smartphone or Apple Watch plans. In fact, as far as I am aware, none of the flanker providers offer the watches or associated plans either. If you would like to use the cellular features of your Apple Watch, you would need to switch to one of the parent providers (see here). Apparently, both Bell and Telus offer a Family Set-up, though I believe you would need access to their networks for the set-up.
If Fido later choose to offer those plans in the future, that update would be available on Fido.ca.
Hope this helps 😀