In order to access full text e-books and articles, you must have your Gateway Library account set up! These accounts are separate from what you set up for the seminary and class registration.
When you click on the the e-book access link you will be taken to the vendor's page for the item. The image below comes from ProQuest's collection.
ProQuest Ebook Central lets you know the terms of access. In this specific instance, you can see that the full text is available for online reading, but not for full download. However, you can download individual chapters for offline reading as necessary. ProQuest has some handy tools, such as computer generated citations (always double check citations. Sometimes the computer can get it wrong and sometimes the wrong things get italicized).
This is the ProQuest eReader interface. The full text PDF is in the column to the right with the table of contents links to the left. Note that the tools from the previous page are now at the top of this page. Note the circled "PDF" icon that you can use to print specific pages. Remember on the first page it said you have 101 of 101 pages available for printing to PDF? Click this icon and then chose the options to print pages 1-101 and you can now have a full download of the text. You can also choose the citation that will show up at the bottom of each page in the PDF (There are two Chicago/Turabian options).
Also notice at the top of the right column that there are two arrows. This lets you navigate from page to page. You can also scroll the PDF if you choose.