Hi Rowena,
no doubt azathothgr can give a more complete answer
but the simple one is :

unzip the .rar file in a folder and you have in there two executable
(read my precedent post about it),
call the folder custompicker,

I have it in my Colors folder in Art Rage folder

all you have to do is to find all (or what you want to have as pickers)
your .col collection from the Resources folder and bring them in that folder,
then one by one drop them on the executable,
you will see the pickers show up one by one,
then bring back the .col files to their place and the pickers to the pickers folder.

Hope this will help !