Take note of the two buckle pieces. One side (the male side) is a flat rectangular piece of metal with a square cut out of the center. The other (the female side) is a buckle with a flap hinge that engages and disengages the piece that buckles into the cutout in the male buckle.
Adjust the belt to the proper length. To lengthen the belt, pull the entirety of the female buckle away from yourself; to shorten it, hold the female side away from yourself, and pull on the loose end of the strap. The belt should fit snugly around your midsection, without pinching or leaving enough slack for your body to move up and down.
Lift the flap on the female side, and insert the male buckle into the opening between the back of the female buckle and the flap you have just lifted. The two small ends of the respective pieces should be facing each other.
Adjust the length as required. You should have enough space to insert both hands between the seat belt and your stomach, but no more. To unbuckle the belt, simply lift the female flap, and pull on the strap leading to the male buckle.
