After installation just launch the app on your phone and grant the requested permission.
Supported are Fitbit, Garmin, Huawei and Wear OS watches.

Every time when you want to use it:
 • Start a Maps navigation on your phone
 • on the watch launch Navigation from app menu
 • directions will be shown on your watch
 • Incoming turns are signaled on your watch by vibrations: left turns will be signaled via two, right turns via three vibrations

You need to install the free wearable "Navigation Watch" app on your smartwatch too.

This app displays turns, distance, direction, speed and arrival time, a map is not shown.
The Wear OS app is not standalone and requires phone interaction in order to function.

See Maps navigation directions from your phone on the smartwatch.