How to cut a hole through both sides of a cube? 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.
After invoking the Knife Tool the status info shows:


For each cut:


Press C to align the cuts
Press Z to cut through 


First cut the vertical then the horizontal edges.



After removing the faces you would need to add more edges (highlighted vertices) or use the Window creator and place a completed window at this position.