Send the pdf file to your desktop, when you are ready to upload the file, go on down past where it says reply to post, below you will see Additional Options, below that you will see manage attachments, click manage attachments and click browse, go to desktop and click on the file you want to up load, that is about it. Just make sure your pdf or any file you upload isn't over 100kb or it will stretch out the screen like it is now.