Hide the rightmost lamp using the walls of Main. Hugging the wall to your right, aim vertically with the dots on the wall. Aim just above the wall and left click throw.

Throw at about 1:43, but can still do significant damage at other times if the T stays on top of Silo to watch outside. Should do about 50 damage to a T standing in the corner.

Pro (Magisk): https://youtu.be/DwybS6MdUHo?t=54 <-- Astralis use nades from two other players to make it a nade stack. The other lineups are more complicated but are explained in this video.