How to kill the Rouges on Lighthouse! Escape from tarkov PvE 

You can zero your scope with page up and page down, So the middel of your crosshair will be where you want to shoot.

Range finder and scope zeroing works well for this

Btw Rouge means red, Rogue is a scoundrel, a villain, a rebel :D. Good tutorial otherwise. Also you can use your sighting range so you don't have to guess at what distance 1 enemy is you shoot a round adjust, shoot another see where it lands, adjust.