You will need to apply for a marriage license at City Hall in Toronto or the municipal office in whatever city or town you are staying in. You can find a list here.
You will need two pieces of government issued ID. If neither of you are from here, both of you will have to prove that these government IDs are legitimate, possibly by getting something from your Embassy or Consulate that says they are. There will be a fee.
You will have 90 days to get married.