The document provides instructions to construct the bisector of an angle ABC using compasses. It involves drawing an arc from point B as the center to intersect rays BA and BC at points E and D. Arcs are then drawn from D and E as centers intersecting at point F. The ray BF is the bisector of angle ABC as triangles BEF and BDF have been proven congruent using side-side-side and corresponding parts of congruent triangles properties.