you can download the install media/DVD like this
--click on "Enterprise Software"
--click on "Product Downloads", search and click on "Software Change Manager"
--click "CA Harvest Software Change Manager Concurrent User MULTI-PLATFORM", then add CA Harvest Software Change Manager V13.0.3 Media(DVDHAV13030E.iso) to Cart and download from Cart
Please notice that this DVD is one for all so once you mount the DVD, go to client folder and follow steps here to install the client