I'm not sure this reflects the view on this thread re the need to use transfer pumps:-
FAQ - Airbus Helicopters
Specifically in that FAQ it says:-
The main tank is the reservoir that continuously feeds the two supply tanks, which in turn feed the engines located on the right and left sides of the aircraft. Each supply tank feeds its own engine. This “feeding” is a continuous process. The supply tanks therefore remain full until the main tank is empty, at which point the fuel levels inside the supply tanks begin to decrease. Operators are advised to refuel as soon as the supply tank “reserve” is tapped – meaning that the main tank is empty."
The pilot does not perform a manual action to switch to the supply tanks. The supply tanks are automatically and continuously fed fuel from the main tank.
It continues:-
The red “low fuel” warning is triggered when there are 32 kilograms of fuel in supply tank 1 and 28 kilograms of fuel in supply tank 2. When this occurs, the pilot has 8-10 minutes left to land, regardless of the conditions and as dictated in the flight manual.
As previously stated, the red “low fuel” warning is generated by an independent indication system with separate sensors in each supply tank. This warning continues to operate correctly even if the fuel gauging is inaccurate.