Open the Watch app on your iPhone
Tap My Watch
Scroll to Available Apps
Find the app you want to install
Tap Install next to the app
Wait for the app to download to your Apple Watch
Make sure the app is installed on your iPhone if required
Open the app on your Apple Watch from the app grid or list
If the app does not appear, check that your iPhone and Apple Watch are connected
If needed, update iOS and watchOS to the latest version