For this super easy matching game you will need to plan ahead to source out your wood discs. I've purchased discs from Amazon, Michael's, and etsy in the past. Stickers were found at a local craft store but you can find them here (I should probably sign up for an affiliate dealio).
Decide on how many pairs you want to make (I did 12 as I only had 24 discs) and get to sticking. Make sure you have 2 of each image.
That's it! I have found that stickers stick best to wood base as is. They stick a little less when the disc has been painted. You can also go over the disc with a coat of mod podge but so far these have stuck and the children know they are not to get wet.