The main problem that you are having is that you have set up the Repeater and the buttons incorrectly. Instead of adding a button over each Repeater element, you just need to attach a button to the Repeater item, and the button will automatically be included (repeated) in all of the repeater items.
See the documentation Wix Editor: Adding and Managing Repeaters (Lists & Grids) for instructions on building a using a Repeater.