Why do you want it if you don't know what it does? :|
Extract the "mod" to main BL folder, right click Blockland shortcut, copy, paste, rename Blockland - editor, right click Blockland - editor, properties, go to the line that says '"bla/bla/bla/blockland.exe"', and change that to '"bla/bla/bla/blockland.exe" - mod editor', and then you are done.