CONSTRUCTIONS

A construction is a geometric drawing for which only a compass and a straightedge may be used.
There are many excellent construction instructions and illustrations here:

http://www.zefdamen.nl/CropCircles/Constructions/Constructions_en.htm

compass a compass:
for making circles;
for transferring the distance
between two existing points
compass ruler/straightedge:
used for drawing a line between two existing points;
no distance markings will be used;
no measurements are allowed
After you've done some constructions, move on to:

Introduction to the Two-Column Proof