Step 1: Get Developer Credentials
Get Sandbox developer credentials for your default test application:
Open the Developer Dashboard. You are prompted to sign in or create an account.
Create a Square application and name it Order-Ahead App.
Choose Order-Ahead App to open your Square application settings page.
Confirm that Sandbox is selected at the top of the page.
On the Credentials page, scroll down and copy the values for Sandbox Application ID and Sandbox Access Token. You need to choose Show to see the access token.
You can optionally create a test account:
Open the Developer Dashboard.
Under Sandbox Test Accounts, choose Add to create a new account.
In the Account Name box, enter Cate's Deli or whatever name you want to use.
In the Country box, select your country, and then choose Create.
To get the Sandbox access token for the new test account, under Sandbox Test Accounts, choose the account name, and then expand the target application.
If you need more assistance, contact Developer Support or ask for help in the Developer Forums.