Just one Fan Token gives you the right to vote in any poll that a team publishes. Your Fan Tokens are not ‘spent’ on a poll, meaning that your supply of Fan Tokens will never decrease no matter how many times you vote.
The more Fan Tokens you own, the more influence you will have. If for example you own 50 Fan Tokens, your vote counts 50 times. But remember, each team has placed a limit on the maximum number of voting rights that any single person can have, to ensure that the vote cannot be influenced by one person or group of people.