Once this is on, your eligible activities count in Harry's automatically. No screenshots or links.
Harry's reads runs, rides, swims, workouts and calories from Apple Health. Not every challenge uses this data; each challenge in the app shows what it tracks.
Open the Strava app on your phone.
Tap You in the bottom-right corner, then the settings gear in the top-right.
Scroll down and tap Manage apps and devices.
Under Services, tap Health. If it's not already connected, tap Connect and allow access on the permission screen, with Workouts & Routes enabled.
On the Health Settings screen, make sure Send to Health is on. That's the switch that sends your Strava activities into Apple Health, where Harry's reads them. Automatic uploads works in the other direction and is optional.
Done? Back in Harry's, open Settings > Data & Syncing. The Last sync time updates within a few minutes of your next activity.