Hello! IP address to use is shown in Hamachi itself. IIRC you can also right-click on the user in network and pick "copy IP". So one player would host the game while being on the network and the rest would use that as IP/Address to connect to them.
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You set the port yourself (with Hamachi, default should work) and then the person connecting would specify the same port (so tell them which one you picked).
So you set the port on "Host" screen, pick Start (and get a player list screen), then the person joins (and shows up on player list), and then you pick Start to get into the actual game.