C1001 Position to measure heartbeat and breathrate

I'm not sure how I should position the C1001 sensor so that it measures my heart and breathing rate. Can someone tell me which part of the sensor should be directed towards my chest? The description confuses me because it looks like the sensor is measuring from the side
According to the wiki, generally wikis will provide detailed instructions on usage scenarios and methods.

I have already read the wiki in detail and don't understand how I should position the sensor. That's why I asked the question.
In the wiki it looks like the sensor measures from the side. But up until now I have assumed that I have to align the sensor so that the red LED points directly at me. But since the sensor only delivers incorrect data if at all, I would like to know how I should align it