KIndle collections Calibre plugin

[atp]

Fairly new to Kindle (Keyboard 3G, UK model) and my Kindle collections, sorted by author, are an irritating mix of Surname first & forename first.
So I installed the Collections plugin because it appears to offer an option to add books from Calibre to existing Kindle collections (and I can switch the names in Calibre)

I started by trying to add 10 books from calibre to my whodunits Kindle collection

Clicked the plugin's icon, and selected
'Edit Collections Manually on your Kindle'
However the window that appears when I try that option doesn't correspond to what is in the 'how to' post in this forum (or another web 'help' page I found), and the rather ellusive popup help doesn't help either.

Please can some kind soul explain how to use this function?