Autotransformer

HI,

I have a boat that uses 240vac in a marina that provides120vac at 50amps. I have a Victron Autotransformer 120/240 100amp.
My question is, with all of the inputs available to the boat (shore power, Genset and inverter), do I just take the output of the selector switch and use for the input of the auto transfer switch? The the output of the autotransformer goes to the provide 240vac to the panel/loads?
Sorry for all the layman terms
Thanks for any help!