Head to Your Dashboard.
Click "Your Bookings".
Here is a list of all your bookings from the "booked" section of Your Inbox.
From Your Dashboard click "Download Bookings".
Under "Download CSV files" click the green download button to download all your bookings as a .csv file, or use the filters to only download specific bookings, (e.g. all bookings made between 01/01/2017 and 01/06/2017).
Under "Printable Reports" click the trip you would like to view.
Here is a week-by-week report of all your bookings, and any passenger information that has been uploaded. You can use the date filters at the top of the page to search for specific bookings/departures.
To download this report as a PDF, right click and select print.
Then under "destination" select "save as PDF".
Here's a quick video demonstration of both options: