Describe the action and reaction forces that occur as you walk along a path.

Action forces is as a result of mass of your body times the acceleration of your motion.

Force = Mass × Acceleration (Newton's second law of motion)

Reaction Forces are as a result of friction force between you and the ground plus air, acting opposite to the direction you are heading. This is described in Newton's third law of motion which states that:

For every action, there must be an opposite and equal reaction.

the part of the wave he is travelling on is the crest