This paper focuses mainly on the classical Variable Structure Control (VSC),also known as Sliding Mode Control (SMC) theory. Firstly, the paper introduces the classical principle of sliding mode control method. Standard sliding modes provide for finitetime convergence, precise keeping of the constraint and robustness with respect to internal and external disturbances. The practical implementation of the proposed approach is exemplified with two simple examples. Step by step design approach is developed and explained. In the first example, a linear sliding function is considered for design of sliding mode controller and in the second example a non-linear sliding function is considered to high light their effectiveness of finite-time convergence and robustness with respect to internal and external disturbances.