Cut a 14" length of ribbon to give yourself enough to work with depending on how long you want your bracelet. 

Cut a length of sewing thread and add a needle. Fold one end of the ribbon and sew through the fold. Hold the fold of ribbon in place. 
Pick up a pearl, thread through your lobster clasp and back down through the pearl and the fold in the ribbon so your thread exits where your tail thread is. Knot them together. (See the image)

After this knot, pick up a new pearl bead. Wrap the ribbon around the pearl and sew through where the ribbon meets the hole on the pearl. Fold the ribbon against itself again and sew through this. (see the image)

After sewing through this fold of ribbon, continue to add more pearls along the design until your bracelet is as long as you would like it to be.

End your ribbon in the same way as you started, folding it against itself. Sew through this fold and add one more pearl. Thread through the pearl and pick up the end link of your extension chain. Sew back down through the pearl and knot against the thread. Thread through the bracelet again, knotting along the way to secure it further. Do the same with your tail thread to secure the bracelet and trim off the excess cord when your are confident it won't unravel.