Update README

Author: ljyloo

README.md

@@ -27,4 +27,6 @@ https://mojang.com/2012/02/new-minecraft-map-format-anvil/
 
 ## Attention:
 
-This is an experimental project, it's highly recommended that you should backup your data before converting. Any data corruption caused by this program should be responsible for yourself.
+This is an experimental project, it's highly recommended that you should backup your data before converting. Any data corruption caused by this program should be responsible for yourself.
+
+This is just a stupid converter, what it actually do is just converting the blocks' data, not include other data such as biome, light and entity. If you don't know how to use the files generated by it, don't use it.