The latest version is 0.3.1 and can be downloaded here.
At some point I may write an installer for DROPP, but for now it has to be installed the old fashioned way.
You can delete the zip file and temporary directory after you have installed DROPP.
If you are new to DROPP you should read the getting started guide next.
Do not forget to use the latest Autocomplete.xml and LuaSyntax.xml files included with DROPP.
Simply delete the diretory you created in step 3 and replace DROPP's Autocomplete.xml and LuaSyntax.xml with the backup copies (you did backup the originals right?).