On minute 6:57 when you perform the ALT+Click to select the "row" of faces, what happens in my case is that is selects the "column" of faces. Can anybody please help me with this one? I have no idea why this happens. 
I already found out what happened! I'm leaving the question here in case someone else has the same issue. You need to click on the edge in the direction you want to make the selection of the faces.
In this case, you must click on one of the vertical edges of the faces. English is not my first language, so I hope you can understand my directions.
