Once you get the spars assembled, you mark and drill ribs to the spars indvidually on the bench. Once the ribs are drilled to the spars you can cleco all the ribs and spars together on the bench before placing in the jig, or you can mount the main spar in the jig, then add the ribs, then the rear spar.
Once assembled in the jig, the main spar gets leveled and all twist removed, then the rear spar is located and tied down so that the wing is square. The wing being level and square in the jig is absolutely essential before beginning to drill the main wing skins. The instructions Van's provides lay it out fairly well; just takes time and patience.
