I'd refer you to this portion of the script:
# CUSTOM_WINDOWS - Here you can set up your own windows to show simple
# data, like the gold window. Basically, you can show a label, and then real
# data. The format is as follows:
#
# :unique => ["Label", value],
#
# As with the CUSTOM_COMMANDS, :unique must be a unique identifier so that
# you can add it into the OPTIONAL_WINDOWS_LIST.
#
# "Label" is a String which will show up on the left hand side. It
# recognizes special message codes, but if you are using double quotation
# marks (" "), then you need to use \\, not \. Ie, it would be \\c[16], not
# \c[16].
#
# value can show one of three things:
# (1) The value of a variable - to show this, just put the ID of the
# variable you want to show.
# (2) Any expression you evaluate - this requires some scripting knowledge,
# but if you know the correct code then just put it in a string. Ex:
# :steps => ["\\c[6]Steps\\c[0]", "$game_party.steps"],
# :keys => ["Keys", "$game_party.item_number($data_items[8])"],
# (3) Playtime - To show playtime, you need to just use :playtime. Ex:
# :playtime => ["\\i[280]", :playtime],
# (4) Other - If you know how to script, then it is possible to add
# special data as well, like playtime.
#
# Additionally, you can make windows that have more than one data line,
# simply by adding further lines. So, for instance:
#
# :combined => ["\\i[280]", :playtime,
# "\\i[467]", "$game_party.steps",
# "\\i[347]", 5],
#
# That would show all of that data in one line. It is the same format, they
# just need to be within the same [].
CUSTOM_WINDOWS = { # <- Do not touch!
:playtime => ["\\i[280]", :playtime],
:variable5 => ["\\i[122]", 5],
:steps => ["\\c[6]Steps\\c[0]", "$game_party.steps"],
:item8 => ["Keys", "$game_party.item_number($data_items[8])"],
:combined => ["\\i[280]", :playtime,
"\\i[467]", "$game_party.steps",
"\\i[347]", 5,
"\\i[262]", "$game_party.gold"],
} # <- Do not touch!
# OPTIONAL_WINDOWS_LIST - Like the COMMAND_LIST, any windows you want to add
# to the menu need to be included in this array. Just add the :unique
# identifier, and that is the position the window will show up. The only
# default option is :gold, which shows the regular gold window. You can
# delete it if you want. To add windows in-game, you can use the following
# script calls:
#
# add_menu_window(:unique, index)
# remove_menu_window(:unique)
#
# :unique is the unique identifier of the window you want to add or remove.
# index is an integer which allows you to choose where the command shows up
# in the list when it is added. If you exclude it and just put:
#
# add_menu_window(:unique)
#
# then it will be the placed at the bottom.
OPTIONAL_WINDOWS_LIST = [ # <- Do not touch!
:gold,
] # <- Do not touch!
To help you more specifically, WiiMeiser is correct in that I would need to know what keys and stars are in your game - ie. are they variables or items or whatever? If so, what is their ID in the database? However, the variable binding script is not necessary as this script allows you to have windows display something from Ruby code.
As a more concrete example, you can see in the script itself that it already has a number of examples:
CUSTOM_WINDOWS = { # <- Do not touch!
:playtime => ["\\i[280]", :playtime],
:variable5 => ["\\i[122]", 5],
:steps => ["\\c[6]Steps\\c[0]", "$game_party.steps"],
:item8 => ["Keys", "$game_party.item_number($data_items[8])"],
:combined => ["\\i[280]", :playtime,
"\\i[467]", "$game_party.steps",
"\\i[347]", 5,
"\\i[262]", "$game_party.gold"],
} # <- Do not touch!
In particular, notice that this line, if included, would make a window identified as keys and which would show the number of Item 8 that the party currently holds:
:item8 => ["Keys", "$game_party.item_number($data_items[8])"],
Then go to the following code:
OPTIONAL_WINDOWS_LIST = [ # <- Do not touch!
:gold,
] # <- Do not touch!
You could have the keys window show up by changing it to:
OPTIONAL_WINDOWS_LIST = [ # <- Do not touch!
:item8,
:gold,
] # <- Do not touch!
If that is still difficult to understand, then please tell me what precisely the keys and stars window are supposed to show and I can tell you exactly what the code needs to look like. So, if keys corresponds to the number of a particular type of item, then I would need to know that and the ID. Or if it refers to the value of a variable, I would need to know that and the ID of the variable, etc.