I'm so pleased that you all try to make the earring. Step 15 and 16 are difficult. But if you have problems, please send me a scan of both sides of your earring, tell me the number of the step where you had the difficulties and I will try to explain what went wrong.
When you arrive at Step 15, you are working on the back side. The ds of your light color ring show in the same direction of your previous dark chain with the bead. Without changing any direction take the middle ring of the center flower over and make first join there. The chain with the bead is on your left. Work the next ds, take the bead under your ring and join there, as you see on Step 16. Work the last 9 ds of first half ring and join to first picot of dark chain (Step 17), then work the ds of second half. Close and only now put your ring in the right position over the bead (Step 18).