Several of the fence boards were cut in half. Some would become leg stretchers; some would become the surface for the bottom shelf. Some would become shorter still for short shelf brackets for the top two shelves of the bench.
I also cut down some of the 2x3s which were eight feet long to begin with to make the front legs of the bench. I'd need three of these.
I predrilled the holes (notice the hex shaft drill bit, suitable for use by the impact driver) and then switched to a countersink driver bit to run the screws through the stretchers and into the legs. I forget the coating/grade of screws I used, I just got some screws long enough for the job that were advertised for use in decking. This is where I fell in love with the impact driver. This was not hard work at all for the tool, and it handled it easily. brtbrtbrtbrtbrtbrtbrt. Next! Man, I'm **never** going back to a different driving tool, evar.
Here's one of the three leg assemblies partly done. If in your imagination you rotate this workpiece counterclockwise 90 degrees, you'll see the front leg (vertical) on the left and empty space on the right where the full length leg will be attached like the short front leg is attached.