FiveStar GF3524M Inverter Manual

My father recently bought a FiveStar GF3524M 3.5KVA 3.5kW Inverter.
He was told by the installer it had a built in auto transfer for load shedding. But cannot seem to make it work and the installer took the manual.
If anyone has a PDF manual or directions on how to enable auto transfer it would be very much appreciated.
I think it is wired such that the inverter is bypassed when not in use as the potential peak use is too high. Which I thought would mean an external transfer switch is required.