Here’s what they’ve sent so far. It sounds like it operates the same as the LRA tank. They sent the installation instructions, but they were in Chinese.
1. How is the tank filled?
   The auxiliary fuel tank is filled through the original fuel filler hole. The internal system splits into two separate fuel pathways, allowing both the main and auxiliary tanks to be filled simultaneously at the same fueling point.
2. How does the fuel get used?
   The auxiliary tank does not directly supply the engine. Instead, it includes a dedicated, standalone fuel pump with a manual switch. When activated, this pump transfers fuel from the auxiliary tank to the main tank. The flow is one-directional and does not allow fuel to return to the auxiliary tank.
3. Is there a fuel level gauge for the auxiliary tank?
   Yes, the manual switch for the auxiliary fuel pump includes a simple fuel level indicator, allowing you to monitor the amount of fuel in the auxiliary tank.
4. Is there an automatic shutoff?
   There is no automatic shutoff feature. The transfer process is manually controlled via the switch. We recommend turning off the pump once the indicator shows that the auxiliary tank is empty to avoid running the pump dry. 
They also have an Instagram video that explains the tank.