The overall dimensions are 8′ x 10′ bit it depends upon where you measure, at the top, mid or bottom points. If you look at page 6 of the plans, the base dimensions are clearly shown in detail. Page 7 shows a color coded isometric view with all parts pointed out.
There are many example photos of this bar in the different phases of construction in the Builder Gallery. Like this one: https://www.barplan.com/gallery/displayimage.php?album=127&pos=0