I searched and the answers do seems to work. How do I sign up for the Mt Everest challenge? When clock in my challenges, I only see tour of California, which I don’t recall ever signing up for.
I found it. You have to start a ride, stop pedaling, click menu. There is an icon there with next to your stats. Click it and on the bottom is grey writing there is a link for more challenges. Appears you can only do one at a time.
When you are riding go to the menu. Click the challenge (in your case Tour of California) then it should give you options to change (believe it’s near the bottom of that screen). You can choose Tour of California, Tour of Italy, or Mt Everest.
Correct only one at a time and Everest has the best reward.