If you are on the latest Reffle Template, you should have the ability to either have a spinning wheel or a scratch card as a visualisation of your instant wins.
If you have chosen the spinning wheel, this will work automatically when you 'enable instant wins' in your instant win tab as you add your competition.
If you have chosen the scratch card, you need to 'enable instant wins' in your instant win tab as you add your competition, then check the 'instant wins reveal' button in your advanced tab, shown below.
You may also have a paid feature, where if you untick the 'instant wins reveal' button in your advanced tab, flashing numbers will be show instead of a scratch card or spinning wheel.