Slide the F-6125 UHMW block over the end of the WD-657 step tube and clamp it to the outboard side of the F-626 floor web. Cleco the step to the side of the fuselage skin. Drill the two bolt holes through the F-626 floor rib using the holes in the F-6125 as a guide (use angle drill). Drill the hole in the WD657 tube for the AN3-25 bolt (use the hole in the F-6125 block as a drill guide, use angle drill). Do this procedure for both side of the external step. Deburr all the holes. It is easier to drill the holes in the web of the floor rib first and then bolt the block to the web before drilling the holes in the tube for the AN3-25 bolt. For the left step I tried to follow the instruction, but the plasic block rotated slightly. Changed procedure for the right step and all came out OK.
