I haven't tried it myself as the camper is still winterized, but this is how I understand you gravity fill the FW tank from jerry cans.
You'll need a short length of hose connected to the city water connection and the other end in the jerry can. Set the Kantleak valve to 'Sanitize/Winterize' and the Fresh Tank Access switch to 'Open'...doesn't matter if the Kantleak valve for the WH is 'Bypass' or Normal'...your choice whether you want the WH full or not. Switch on the water pump and it's suction will draw the water from the container into the fresh water tank.
If you want to sanitize the FW tank, you'd draw the bleach solution into the tank the same way.
Once the fresh water tank is full, switch the Kantleak valve to 'Normal', and the Fresh Tank Access to 'Shut' and switch the FW pump on to meet your fresh water needs.
I'm betting transferring the jerry can will be much slower than pouring them into a old style gravity fill connection.
Dave