You first need to create a new BTCPay store:

  1. Log in to your BTCPay Server instance
  2. Go to Stores menu
  3. Click on Create a new store
  4. Enter a name
  5. Push Create

Now you need to pair the BTCPay client in Node-RED with the BTCPay store:

  1. Navigate to Stores > Settings > Access Tokens on your BTCPay Server
  2. Create a new token
  3. Leave PublicKey blank
  4. Request pairing
  5. Copy pairing code
  6. Open your Node-RED instance
  7. Drag & drop the btcpay api node from the palette to the workspace and double-click on it, to open the node editor
  8. In the Client dropdown menu pick the Add New btcpay-api-config option and press the pencil button at the right to add a new API configuration
  9. Enter the https URL to your BTCPay Server instance
  10. Paste the pairing code you copied on step 5
  11. Click the Pair client button - the private key and token fields will be automatically filled with your api credentials
  12. Push Update