To attach a file to a new post, simply click on the "Options" tab at the top of your post composition page, and click on the add/update button. Locate the file that you want to attach from your local hard drive.
Only certain types of files may be attached: these are the valid file extensions for files to be attached to this forum: bmp doc gif jpe jpeg jpg mp4 pdf png psd txt xls zip. The file may not be larger than 640k.