Can you be more specific as to what doesn't make sense? Is there a specific sentence, or some concept you're not getting? (like you don't get how to place them, or what makes them appear, and so on)
Another, easier way to create systems is to use Pontus's EVO Developer's Map (available on the add-ons page). With that you can make your systems graphically (instead of messing around with so many numbers).
As for changing the resource ID, click on the resource and go to get info (should be command-I). This lets you change the ID (assign it to something 128 and whatever max there is, that isn't taken up to prevent replacing).
Hope this helps somewhat.
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Mike Lee (Firebird)