This is a tutorial on simple 1v1 defending principles. This type of defending is predominately used in the defensive third of a field with the defending team. This technique can be adopted by all positions on the field, but the full backs (right and left backs) would benefit mostly from this.
This video does not teach how to slide-tackle or how to win the ball aggressively. It teaches simple concepts of how to approach, stay and steal a ball from a defender.