Walking like a catwalk model is easy.
You only need to know three things.
First of all, make sure that, at all times, your hips are ahead of your shoulders. Throw out your hips and pull back your shoulders.
Second, cross your legs as you walk. As you walk, when you bring forward your left foot cross it over your right foot. Then, as you bring forward your right foot, cross it over your left. Keep this up as you walk.
Third, when you reach the end of the catwalk, pivot on the forward foot. Left or right, it doesn't matter, but pivot on the forward foot.
Then walk back. Again, hips over shoulders and legs crossed.