Removing Vantage Sills/ Cost to paint?

[millsjq]

I am fortunate that I found someone that recently purchased a set of N420 sill but sold his car and was able to buy them at a reasonable price. I plan on taking them to be sprayed in the next few days, and have read the AM ship manual on how to remove and replace. However, it speaks of clips that require “being released” and some have written that the clips are tricky. Can someone explain where the clip are located the procedure required to remove the sills, or maybe a photo?
On a spate note, how much has been the cost for painting the sills?