ambi is a wireless temperature sensor (WTS) that when placed in a room adjusts your Tado heating system to achieve temperature you set where you are sitting.
Tado is a great heating control system with one minor flaw, the tado temperature sensors are positioned next to radiators and not where you are sitting. Just tell the ambi WTS which room its in, ambi gets the rooms from your tado home profile, and the ambi WTS will communicate with Tado and do the rest. Inside the ambi WTS is a digital temperature sensor which ambi uses to measure the actual temperature within the room. The ambi WTS will dynamically configure the Tado system and monitor the room temperature to achieve the temperature you set for the room instead of just by the radiator with the Tado thermostat is positioned.
ambi does not replace your Tado Control App, you still use Tado to set your room temperature targets and schedules, ambi just knudges the Tado system behind the scenes helping it achieve the actual room temperatures you set in the Tado system.