How do I turn on automatic GPS tracking

[Fennija]

When I go to my exercise activity shortcut for walking it says underneath “GPS won’t turn on”

I can’t find how to switch on the function for GPS to automatically start when my Charge 5 recognises that I’ve started a walk. I usually forget to turn it on myself so this would be useful. 
i’ve tried swiping up on the shortcut for walk but nothing is there. Help pls

[vbenar]

I'd like to know the answer, too.

I've read that for some devices, gps won't turn on for activities that are automatically detected.  Can that actually be true?  

(My cheaper garmin recorded distances with automatically detected walks.)