When opening a sensor by clicking on its name, a new page will appear with the sensors telemetry data on the left hand side. On the dashboards in the middle, you will be able to see activations for this particular sensor (see figure below). By clicking on a sensors activation, the telemetry data on the left will adapt to the time frame of the activation's start and end date. 

In the specific example above, you can see that we have selected the second activation from the activations list in the middle console. The sensor data on the left hand side is therefore displayed for the activation time frame from 2nd of May 2023 to 30th of May 2023. 

If no activation is displayed, you will not see any sensor data. You will have to create an activation first or move back to the previous site and select "show all telemetry".