How does it work?
The game host starts the round, and the game
begins. The dealer then asks one of the players a
question, calling them by name: “Tell me, John...” The
questions usually pertain to the current location. This
is prudent, but not mandatory. Questions are asked
once; no follow-up questions are allowed. Responses
can take any form. The player who answers the
question proceeds to ask any other player a question
of their own, but cannot ask a question of the player
who just asked them a question. The order in which
the questions are asked is established by the players
themselves and based on the suspicions they have
after hearing the questions and answers. Your goal is
to figure out which player is not on your location and
therefore... is the Spy!

Find the official rules here: https://www.cryptozoic.com/sites/default/files/icme/u30695/spy_rules_eng_0.pdf