The information is on page 4 of the documentation, "How to Download Dorchester." It says you need to download the Pedalboards, Anderton Synthetic Impulses, and Kickmaster from the Anderton Collection.
The impulses appear in the Cakewalk Content folder on the C: drive. You can move this folder anywhere you want, just remember where it is so you can navigate to it when following the instructions for loading custom IRs on pages 14-17.