The SIM card is already installed in the FINDER for the Online Tracking. You do not have to worry about anything else, as the price for the M2M SIM card is included in the licence for the FINDER portal.
The integrated M2M SIM does not prefer any particular mobile network, it automatically chooses the best reception. Your FINDER can therefore connect to the strongest mobile network at any location. If a network fails or offers poor reception, the device automatically connects to the strongest mobile network.