Doesn't seem like much accomplished for the time, but this is drilling into steel frame sections.
There are four areas where the cabin tube frame is to be fastened to the mated fuselage: upper left and right at the leading edge of the aft fuselage, and left and right down lower in the area of the eventual instrument panel.
One hole is provided by Zenith on each of the corner tube sections. Once cleco'd, then the other 8 holes must be first drilled to #40, then updrilled to #30, and finally #20. Drilling #30 and 20 holes is easier because there's already a hole there and more to "bite" with the drill bit, but those first #40 holes take forever. Went thru 2 bits already.
Once the 4 corners are secure, then there are angle braces on the lower forward side to further tack it to the fwd fuselage longerons.