Reference

Interaction with other plugins
ActualTime — records the working time at each stop. When the technician stops the travel timer on arrival, Waypoint starts an ActualTime task on that ticket automatically. The resulting time is linked to both the ticket and the route.
gappextended — provides the mobile API and the geolocation storage that Waypoint relies on, including the permission that controls access to the Geolocation section. Waypoint cannot run without it.

Impacted GLPI items
Assistance
Tickets — "Linking to route" option and Waypoint tab
Administration
Profiles — Waypoint rights
Geolocation — technician positions and live routes
Routes — route history and detail
Setup
Locations — coordinates are required

Current scope and good to know
To set expectations correctly, this is what the plugin does not do today:
Navigation happens in your maps app. The route screen is an ordered list of stops, not a map with turn-by-turn guidance. The Map button hands the destination over to Google Maps, Waze or whichever app the technician prefers, which is also what gives access to live traffic and voice guidance.
Arrival is confirmed by the technician, not detected automatically. There is no geofence: the work timer starts when the technician stops the travel timer on arrival.
Timer notifications are local to the technician's phone. They show that a timer is running; they are not GLPI e-mail notifications to supervisors. Supervisors follow progress through the Live Routes tab.
Reporting is done through GLPI lists and the CSV export, not through dedicated KPI dashboards.
Every route calculation consumes Google API quota. Creating or editing a route triggers several calls. Disabling Billing includes return trip roughly halves that consumption.
A ticket visited in more than one route appears once per visit in the CSV. That is intentional — each visit is a separate journey with its own times and distances.

Troubleshooting
Symptom
Most likely cause
The Waypoint entry does not appear in the app.
The user is a self-service account, lacks Waypoint rights, or 
gappextended is disabled or below 2.21.0.
A ticket is missing from the selection list.
"Linking to route" is not set to Yes, the ticket is not assigned to that technician, or its location has no coordinates.
The route cannot be created.
Missing or invalid Google API key, or the required APIs are not enabled for it.
Distances are recorded as zero.
Location permissions were not granted, or the GPS had no fix when the trip was started or stopped.
Tracking stops when the phone is locked.
Background location permission is missing, or the operating system's battery optimisation is suspending the app.
Positions are recorded that do not belong to any route.
Enable user geolocation is switched on. It is not compatible with route tracking; disable it.