Step 4: More drilling and gluing
Take the 23 cm piece. On top of this piece make a mark 2 cm from each side. Drill a 10 mm hole 1 cm deep on these marks. Glue the dowels in it.
Do the same for the 20 cm piece.
Measure 24.45 cm from the straight cut end of the 65 cm piece and make a mark 2 cm from each side and one in the middle. Drill a 10 mm hole 1 cm deep on these three marks.