In order to use Cashier you must have a payment gateway set up.
To set this up, follow these steps:
- From "Shopify Admin", select Apps.
- Select Cashier.
- Select Settings.
- Select Payment Information.
- Navigate to Stripe and set up an account.
- Back within Cashier select Connect next to Stripe.
- Enter the email address you registered with.
- Enter the password you selected when registering.
- Select Sign in to your account.