I'm trying to make a hole through the face:
So it will come out just like this hole on the other side of the mesh:
If it doesn't make sense, i'm saying this: On the first picture, It clearly has no hole.
On the second picture, It is the other side of the CUBE , i have used "knife" tool to cut the hole but it didn't go through, so i'm trying to make that exact hole, on the first pictures face so i can make a window.