Hey @Joanart, welcome to the seller community! 🙌🏻

If you have a Samsung Galaxy S5, you should be good to go with any of our mobile card readers. For specifics, have a look at supported devices.

To get a new reader, have a look at our Support Center: Get a Free Square Magstripe Reader. In addition, you can find a refresher on getting set up for card processing here: Square Get Started Guide.

Wishing you all the best with your show! Don't hesitate to follow up with us if there's anything further we can do to help. 🙂