Adding items is done via the
rug_inventory_fadd.sqf function found in the main rug_inventory folder. The main point of this function is actually to STACK the item itself to avoid having a whole inventory full of items with the same name and purpose. Now, in the demo mission and by default, this function is precompiled into the global variable
RUG_Inventory_fadd (if I remember correctly - you can check what precompiles where from RUG_Inventory.sqf). I believe that there is a description of how to use the fadd function in the script header of said script, so you might want to look there. However it goes something like this:
Player setvariable ["rug_inventory", ([(player getvariable "rug_inventory"), "MONEY", 1000] call RUG_Inventory_fadd)];
Or in a more readable form:
_newInv = [(player getvariable "rug_inventory"), MoneyItem, 1000] call RUG_Inventory_fadd;
player setvariable ["rug_inventory", _newInv];
MoneyItem being the global variable assigned to the item and the number (in this case 1000) being the amount. NOTE: for the above to work the script has to be precompiled (RUG_Inventory_fadd = compile loadfile "RUG_Inventory\RUG_Inventory_fadd.sqf"), which is done automatically in my demo mission or when RUG_Inventory.sqf is run for the first time (such as when opening your inventory). Furthermore, MoneyItem has to be assigned to a global variable as well - I think if you look through TemplateInventor1.sqf (or something like that) you should find examples on how it works.
And also note: my syntax might not be correct! Verify it yourself. But here's the short version of how things work:
Your inventories, stored in the "RUG_Inventory" variable, is simply an array of arrays. Each entry in the array is an item, which in itself is an array (as you've noticed when you've tried adding your own items). That is how you can easily create inventories by binding the items to global variables, as so: YourInv = [Item1, Item2, CrowBar, FunkyShoes1]; Player setvariable ["rug_inventory", YourInv]. However, the problems come when you start to stack items (as in more than one FunkyShoes, or more than one item of "money"). This is solved internally in the default Use/Take/Drop scripts -> and also when using the fadd and fremove functions. So basically, if it weren't for stacking, adding items would be a lot easier (removing them is a whole different matter though..).
Aaanyway...point of the whole thing is: I suggest you use the functions that come with the scripts. They should save you a lot of trouble
Wolfrug out.