ok unzipped or zipped either one, you place in your addons folder, your addon folder is in different areas depending on what kind of computer you have
if you have windows:
Program files/ Blockland/ Addons <---- place unzipped/zipped addon folder here
If you have macintosh:
Applications/ Blockland v10/ Addons <---- Place unzipped/zipped addon folder here
Now once in your folder, start up blockland, click start game and there is a button that says addons, now a button that says the addon you added to the file appears and you make sure it is checked.