You should have received an email with all the setup instructions to log into the Square Point-of-Sale (POS) app which will consist of:
Download the Square POS app from the iOS App Store or the Android GooglePlay store
Run it and type in the 12 digit Device Code sent in an email
It will ask for a passcode. We share a passcode for everyone in the cashier role and that passcode is:
1234
Important: Never hit Sign out or you'll need to type in the Device Code again
At the bottom of the app is the main navigation:
Checkout - for processing a transaction
Transactions - for reporting
Customers - for adding customers
Notifications - locked off (can't remove it)
Hamburger menu - most of this is locked off
Both Android and iPhone can read contactless card payments. The Square Readers are more robust and can take the chip reader if needed. To pair a Square Reader device to your phone:
Hold down the button until it flashes orange lights
In the Square POS app, go to the More hamburger menu at the bottom then go to Settings -> Hardware -> Square Readers -> Pair a new reader
Pairing uses Bluetooth and should be trivial
Note: There's no way to turn off the Square Reader! The battery should last for weeks but may need to be charged before each monthly.