It is very unfortunate that this basic feature is completely missing from QBD. When I used Excel for accounting, that was the easiest column to add.
I am not in need of instructions on how to record my hours. That is already working fine. Not sure why you included these instructions that I clearly didn't need.
Please raise this issue internally. I've already highlighting this issue here and other places. I shouldn't need to do it in the Application as well.