Copied from the disclaimer from the link you provided:
To earn the $20 Cash Anniversary Bonus, you must become a New Tangerine Client using the Orange Key “2020” and successfully open your first Tangerine Savings Account, Tangerine RSP Savings Account, Tangerine Tax-Free Savings Account or Tangerine Chequing Account with a minimum initial deposit of $100 by June 9th, 2017. Accounts are deemed successfully opened when you have satisfied the Account Terms and Conditions and the Account is without restrictions. The $20 Cash Anniversary Bonus is limited to the first 5,000 New Tangerine Clients to use the Orange Key “2020” between May 16, 2017 and June 9, 2017. Bonus deposits will be made to your first opened Tangerine Account within thirty days of Account opening. Limit of one (1) $20 Cash Anniversary Bonus per Client. Where two New Tangerine Clients open one joint account using the Orange Key “2020” only one (1) $20 Cash Anniversary Bonus will be paid to that account.
Maybe read it again?