This document introduces different parts of a truss including joints, members, and reactions. It then provides the essential formulas for determining the stability and determinacy of trusses based on the number of joints (j), members (b), and reactive components (r). The remainder of the document works through examples of truss structures, calculating values for b, r, and j, and determining in each case whether the truss is stable/unstable and determinate/indeterminate based on the formulas.