Just double click on the dowloaded file, it will install or replace the old W2E version. The occasional user can create an high quality epub without worrying about the source document quality, while professional can create an easy editable, well structured and valid ePub file. W2E is intended for occasional users and professional use. Neither is W2E an ePub editor, please look at Sigil or other similar product if you need to edit and modify an existing ePub. Please look at Calibre or other OOo extensions available on the Internet to do this kind of jobs. If you need to obtain a pure wysiwyg ePub file, W2E is not for you. It does not just convert an existing document to ePub.
If you need a good ePub document and you can use the OOo Writer Word Processor, W2E is your tool. Simply write your document with the OOo Word Processor and W2E will make an ePub file using the best traditional typographic rules, by applying a predefined style sheet (CSS). Just simply one click, you can obtain a well formatted, easy readable ePub file from almost any document.
Writer2ePub is an extension that creates an ePub file from any document openable by the OOo Word Processor.