Cover tier in base color (white in the picture.)
I then make a template for the color wrap. Measure or compute the outside measurement of the tier. Cut a strip of paper to match the desired height and width. Fold in half. That center line is the high point. Keep the paper folded and draw a diagonal line to nearly the bottom. Trim away excess. You now have a pattern.
Lay it on the color fondant and cut our. Carefully roll the pointed ends of the color fondant toward the center so that you can pick it up. Brush a tiny bit of water onto the fondant only where the wrap will go. Pick it up and apply the tallest part to the tier and then unroll and wrap it around. Smooth it out.
Extrude a rope of darker color fondant. Using a small brush, apply a tiny bit of water to the top edge of the color fondant wrap. Apply the rope. smooth it out if needed.
It's easier than it looks.