Here are the steps to get the Braintree keys
Step 1: Log in to your Braintree account
Step 2: Click on the Settings icon and choose 'API' from the dropdown list
Step 3: Under the API keys, click on the 'View' button to obtain the public key, private key, and merchant ID.
Copy these keys to the PayTraQer screen to connect your Braintree account with Xero.
To know how to integrate Braintree with Xero, read this article