A-1 is the distance from the working edge of the rail to the first dowel.

The same measure can be used from the end of the leg.
When the centers are all marked, bore the holes.

Insert the dowels into the holes and make a trial assembly.

If any rail is twisted from its proper plane, note carefully where the error is, take apart, glue a dowel into the hole, that is wrong, pare it off flush with the surface, and re-bore in such a place that the parts, when assembled will come up true.

When everything fits, glue and clamp together.
_No.9.A toe-nailed joint_, Fig.