Understanding the Plan
The diagonals are perhaps the hardest to understand and also the least used for the purpose of model making. Usually you will glue up layers of wood from which to carve the model along planes which represent either buttocks, waterlines or sections, but not diagonals.
If you do not understand the lines plan clearly, you may want to make a rough model of any shape and cut it up with a saw to represent the action of the planes passing through the hull. Of course, if you do each of the four views you will need four models, unless you plan to do a lot of gluing.
You will see that the templates to be cut out of the centerfold* (see below) represent several sections, including a transom. The sections are to be used outside of the model hull, so they are drawn to be cut out as templates, the reverse of the way they appear in the actual body plan.
The section templates should be made out of some thin, stiff material. The centerfold should be heavy enough*, but if you are making templates from your own lines plan you might want to consider transferring the shapes to thin cardboard or poster board, Formica, or even veneer-thickness wood. You want a stiff, flat template that does not wander away from the position of the section. After a little practice, you will find that a sharp, straight-bladed knife will make a better cut through cardboard than scissors will.
*The centerfold was originally planned by Rob as a large removable insert on heavy stock from which templates could be cut. It is shown below in reduced size.