This forum is primarily dedicated to the Ruhavik application. Therefore, we cannot help you with another application.
If you want to track 3 cars at the same time, then you can try to use the Ruhavik app. You can register 3 tracking units for free.
You will need to create a unit for each tracker in the application and then configure the trackers for the server and port specified in the unit settings.
If you have any questions about connecting to the Ruhavik application, you can write to us about it.