The configuration should be in part 1. Scroll down a little until you see this:
[rgss] Â #=====Set character slots properties =======================================
 WEAPON_KINDS = [0,0]            # number of weapons,  0 = weapon
 WEAPON_KIND_NAMES = ['R-Hand', 'L-Hand']  # custom name of extra weapon slots
 WEAPON_KIND_POWERS = [100, 95]      # 100 = normal power, 90 = 90% power
                      # Leave empty or put nil inside
                      # if you want the default names.
 ARMOR_KINDS = [1,2,3,4,5,6]
 # 1 = shield
 # 2 = helmet
 # 3 = armor
 # 4 = acc
 # 5 = and more : extra slot
 EXTRA_SLOT_NAMES = ['Ring','Chain']
 # Name of the extra slots in equip window
 # You need as many words as there are '5' or more in armor_kinds
 # The first order of the slots names reflect the order of the 5 in armor_kinds
 # Put (5) or more to in the armor name to have it assigned to the extra slot
[/rgss]
That's a little altered because I edited the script to my own needs the last time I used it but basically you're looking for EXTRA_SLOT_NAMES =
in that, you can list all of your names seperated by commas. For example, I created "Rings" and "Chains" as extra accessories.
If I wanted to define an accessory as a ring, I put it's name in the database followed by "(5)" as the comments suggest. For example: Ruby Ring (5) as the item's name. For slot 6, we just use a 6, like: Gold Chain (6).
Do not worry because the numbers will NOT show up in the game's screen. The script hides them and makes them go to the right slots in-game.
You can also use this technique to create cursed items, 2-handed weapons, and 2-attack weapons.
I hope that explains it, and if you have any other questions, just ask. I've done quite a bit of work with this script in the past.