Follow the very simple form on the site:http://www.mergepdf.net/
Combine PDF documents:
1. Select two (or more) PDF files to be joined together by pressing "Pick files..."
2. Press the "Merge PDF !" button to upload and combine the selected documents!
I found uploading the documents in a logical order ensured they were ordered exactly how I wanted them. Great little site that does not require downloading of other programs.
Hope this helps someone else out. I have found it useful in the past.