As an amendment to the above advice:
1. It isn't recommended to have a nameCheck.txt. It does absolutely nothing.
2. You should leave your add-on in a normal folder (not a zip) while testing it. It'll load faster (Blockland doesn't have to unzip it), and it'll be easier to re-execute (you can use exec() and e() directly with folders, with zips you have to run discoverFile( path ) so Blockland will update it).
3. Description.txt has no mandatory scheme to it. It's simply a file to explain to people information about the add-on, it's quite useful. The most common format follows:
Title: Your Add-On Name
Author: the_stitch
This is a one line description of your add-on.