you have to buy an external thermostat. The chest freezer on it's warmest setting is too cold. It's a freezer
Popular optionsa round here are Ranco, Johnson A419, and LOVE.
You can find pre-wired version for Ranco's and Johnsons to you just plug it into a wall and plug your freezer into and set your temperature. The Love gives you a much smaller package. Nice for Aesthetics on something like a keezer.