Well, what reader do you have? The one that plugs into your phone using the headphone jack? Or do you have the contactless chip reader that does ApplePay and chip cards?
have you downloaded the app? https://squareup.com/help/us/en/article/5243-download-the-square-app
here is a guide to using square and setting up an account. https://squareup.com/help/us/en/topic/226
Here is a guide to using the readers. https://squareup.com/help/us/en/article/5413-getting-started-with-the-square-chip-card-reader
https://squareup.com/help/us/en/article/5174-swipe-card-payments-with-the-square-reader
