Use of each:
notepad : is a bit tweaked console-color notepad available in browser via bookmark
markdown-editor-need-www : live-preview markdown editor; does GET 2 Markdown JS files online
live-preview-markdown-editor-offline : will give a pure offline live-preview markdown editor
These will work directly by copy/pasting the content in Browser URL and pressing "Enter". Then you can bookmark it on render with proper name and use whenever want.