It's easy! Just follow the steps below:
Step 1: Log in using the id and password provided to you by Teragren.
Step 2: Select "Document Store" from the main menu.
Step 3: Navigate to the section containing the documents you wish to download.
Step 4: Click on the download link of the document you wish to access. This will open the document in Preview mode where you will find a "Download" button at the bottom of the preview. Download the document to your desktop and re-save.
You will need Adobe Reader to access most of these files.