Stand wing up vertical on rear spar, clamp square to work bench. Drill #40 and cleco W21-09 x 2 Clip (part of Aileron Bell Crank Assembly) to W19-01 Aft Upper Wing Skin. Drill same #30 and cleco. Bolt W11-06 Root Wing Attach Assembly to W08-01L Left Main Spar. Bolt W20-03 Root Rib Attach Angle to W08-01L Left Main Spar. Bolt W13-02L Root Rib Attach Angle to W12-01L Left Rear Spar.