yeah I hardly ever use "duplicate special". In the tut I use shift-d (duplicate with transform).

For the individual faces...

shift-D the face, then rotate 90 deg, then press shift-D two more times.

For extending the cooler...

Shift-D the bottom section, Y-translate up and line up the bottom edge by eye, then press shift-d 3 more times.

Give that a try I think you will like it.



As a note I should probably spend more time explaining what I am pressing and doing in my tutorial but I slap them together so fast that I sometimes just assume folks can see what I am doing since I use the marking menu system for almost everything. But for things like using shift-D duplicate there is no visual feedback to give folks a clue to what I am doing unless they already know it. I will keep that in mind for future stuff I record.