Hi Mate, i was able to make a quick recording showing how i approach clearing the trench.
Not to mock you or anything, just to proove, that it can be done quickly and efficiently (obviously i know all the mechanics and have played this game for a long time, so i dont expect this to be "intuitive").
I would be happy to see another recording from you where you try to reproduce my strategy (there are some charotic factors obivously, like the type of reinforcements, movement of enemies, bullets, mortar, etc.)