You'll need to use HTTP nodes in your workflow that can POST and GET a specified URL.
First, POST a file to the POST /v2/inferences/enqueue route. You'll need you API key and Model ID.
Authenticate using an Authorization header containing only your API key.
The Model ID must be sent as a form parameter.
In this POST response, there will be a polling_url attribute, save its value.
Wait 3 seconds.
Loop GET requests on the polling_url until the response contains a result_url .
Note: make sure to configure the node to not follow redirections.
Alternatively, loop on the polling_url until it redirects to the result.
Important: in all cases, wait at least 1 second between each poll.
A GET request to the result_url will contain the result payload.