How to install optical level sensor

[joljols]

I cannot find any guide on how to install the level sensor. The product also didn't come with any paper to explain what to do.. I have:
-Level-Sensor, optical, Version 2
-PL-LF-S12, angled
-PL-LF-Base2

I can see the image here https://store.aquariumcomputer.com/pl-lf-base2-2/ but why is there no explanation of how it works and example photos how to install it? No guide on how to set it up on the app? Don't understand why not more information is given anywhere.

My questions are:
- how does the level sensor work, does it detect if there is water or not and send a 1 or 0 signal?
- Can you also measure the water depth with it, or why is there also a way to position it vertically it seems?
- Where do you position the level sensor, outside the water of the tank I presume?
- How do I get the readings on the ghl app?

Thanks for guiding me in the right way