You can download Stops for Apple Watch from the App Store.

If you have already downloaded Stops for Apple Watch from the App Store, it is automatically installed on your Apple Watch. You may run Stops app from your Apple Watch dock.

You may get more help on official Apple documentation for Watch OS.

When you first time open Stops App on your Apple Watch, it may ask you to login even if you already have been authorized in Stops on your iPhone. 

Open Stops App on your iPhone and on your Watch at the same time and login account will be synchronized for both of your devices. If you want to log out, we also suggest you to open Stops App on your iPhone and your Watch before logging out. 

Open Stops App on your Watch and tap the button “Share My Location” on its main screen. On the next screen choose one of your contacts you want to share your location with.

You may share your location using only Stops m