Outer wing to inner wing - how?

After a frustrating day of one step forward, many more back, can anyone advise how clip #302532 (spire nut) should sit in terms of trying to fix the outer wing skin to the main wing panel? It might be a stupid question but after a long day it's not clear to me at all. And, how many of these clips do I use? Which wing panel are they fixed to?

Thanks in advance.