Make a request to the Connect URL as shown in this example: 
curl --request POST \
  --url https://connect.flatpeak.com \
  --header 'Content-Type: application/json' \
  --data '{
  "connect_token": "<connect_token>",
  "route": "session_start"
}'
The response will be one of the predefined pages listed below. Your application must support handling all of these pages.
The BACK action is available on every page, it lets customers reliably return to the previous step.