When creating a new thread or response, you'll see a "File Manager" link on the "Full Reply" or "New Post" page. When selecting this option you'll receive a popup which will allow you to attach files to your post.
1. Click "File Manager" to bring up the "Attachment" window.
2. Click "Browse" to bring up the file browser window; this will allow you to browse your computer for any files or images you wish to upload; please note that you're bound by whatever the "allowed file type" setting is in the control panel.
3. Click "open" on the file you wish to upload.
4. Enter a description of what the file is (if you want to).
5. Click "add file" to add another file, or "done" to close the window and complete your posting.
Please note that you must enter some text in both the "subject" and "post" fields when responding otherwise you will receive an error; you cannot just respond with an attachment