This plugin makes your attachments more effective. Supported attachment types: Word, Excel, Pdf, PowerPoint, odf, ods, zip, rar, tar, mp3...
Use WordPress media uploader when you create new page or post (Insert / Upload button) and upload your files. No special things required. Plugin uses wordpress attachments.
Go to Auto Attachments => Gallery Settings from accordion and set Thumnbail & Big size dimensions what px you want. And please use Rebuild Thumbnail page.
Go to Auto Attachments => Misc. Settings and if you want to use multi-column list set yes "List view of Files" (default No).
Go to Posts (or Pages) -> Create New (or Edit). You will see a new button with a paperclip. Press this button and follow the instruction.