Once you has accumulated the required number of stamps to complete a milestone, as indicated on the Stamp Card, you will be awarded with the designated reward/giveaway. The reward/giveaway will be accessible from the Stamp Card page.
At the partner location, show your voucher to the outlet staff and swipe to redeem. If the partner has multiple outlets, you will be required to choose the correct outlet upon swiping the deal, before confirming redemption.