Yeah, that did not make a whole lot of sense to me and I build stuff for a living :B.
By 'spacer' I think he means a vertical 2x4 that ties the panels together. Each panel lays against half the 2x4. You could screw the 2x4 to one of the panels permanently.
But what is this 'kicker'? Maybe he means a diagonal support perpendicular to the lattice' plane? When he says 'frame', does he mean the frame around the lattice or the frame of the RV? I suppose either one would work.
Sounds like a good sturdy design for long term. For short term, I would be inclined just to attach the panels to each other, and to the underside of the RV, with matching white zipties. Spiffy.
3/4 timing in a DIY van conversion. Backroads, mountains, boondocking, sometimes big cities for a change of pace.