I sent you an email about this, but don't get impatient. People have lives too. As I've said in the email, try reading about Chapters and Islands and the island.xml file yourself. It's not too hard if you're dedicated enough.

I will make a tutorial when I have time, but I need time.

thanks puggsoy i am begging to be impatient thanks puggsoy!
it's just some one told me how to do it before and it didn't work!

just wait and lift those goo balls of yours

PLEASE only make chapters that override chapter 2 of the game, however. There are a lot of GooTool complications when overriding chapter 1 (and I've only seen one addin that actually overrode it and worked well). Puggsoy's chapter is a good place to start as a tutorial. Rename his .goomod to a .zip and poke around until you figure out how everything works.

I'm planning to have a go at overriding Chapter 1 sometime, it seems interesting, and not too hard.

Okay then, good luck!
Just remember to put everything in merge files, rather than in the compile directory. But you probably already know this.

Yes, we know!

Yeah. I'll probably have this page open (http://goofans.com/developers/world-of-goo-level-editor/reference-guide/...) all the while I'm making it. XD