Sending json response to dashboard

Ok - I am stuck. I understand the code needed to extract the data from a website’s API - which I have done here. But what I want to do is send the "reservoirelevation of 999.49 to Cayenne’s dashboard where I can show it as a sensor value. I know I use Cayenne’s API and MQTT to do but I am not clear on the next steps after importing the cayenne mqtt on the terminal

Cayenne Rest API has been discontinued.