Where/how to place the PAPI lights?

[ForrestFox]

Is there any specifics on how and where I should place the PAPI lights?
I take it they are supposed to be in front of the air run (facing towards the cockpit to help the pilot), but how close to the runway should I place them?
And is one enough, or should I line up several?

[TwoCflyer]

they are typically found on the sides (typically the left when landing) of the runway near the landing zone (big white markers).

I like to put them on both sides (left and right), both ends, and about 1-2 tiles from runway edge. I typically place them in the center of the landing zone big white markers unless an exit needs me to adjust.

https://en.wikipedia.org/wiki/Precision_approach_path_indicator

https://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/lsg/papi/

[ForrestFox]

Thanks for the answer :)