Here I am drilling the main wing ribs to the main spar.

The spar comes with pilot holes where the ribs mount.

I drew lines down the centre of the flanges at the front and back of the ribs. Then I clamped the ribs in place, making sure that I could see the line on the rib through the holes in the spar. Then I drilled the full size holes through the spar and rib, putting clecos in as I went.Drilling wing ribs to main spar

Here is the right wing with all the main ribs clecoed on.

It felt pretty good to finally have a large part taking shape before my eyes.