For borrowable books, you'll need Adobe Digital Editions. To read borrowable books on a mobile device an ereader is required. Bluefire is the recommended free ereader. You can't download and read borrowable books on a public computer.
The rules vary according to the book. In some cases, you can print or download up to 20% or a single chapter of a given book. In other cases, there are no restrictions on downloading. Some books are text-based only and cannot be downloaded.
Some books can be "borrowed" by clicking "Read this book offline in Adobe Digital Editions" to send to your Adobe Digital Editions account.
You can save titles to My Books list, create a bibliography in various citation styles, and send it to your email. You can see specific instances of your search term in each search result, and also search within the text.
Once connected to the book through the library catalogue, scroll down to advance pages or expand the table of contents from the left hand menu to jump to a section.