Sorry for any confusion. The link I provided in the last post is the download link for Sequel 3 from the Steinberg server. It provides both the Windows (.exe) and Mac (.dmg) installers. You must download the link, which is a .iso disk image (an image of a physical disk installer). Windows 8 and all Mac OSX operating systems can mount an image for you without any additional steps, meaning you can use the installers immediately after downloading it.
The instructions I provided were in case you were running a Windows 7 operating system (because you didn't specify your operating system) in which case you would need to burn the downloaded image to a DVD-R in order to run the installer. Or if you do not have a DVD burn, you can use the link to the software that will mount an image for you on Windows 7.http://www.slysoft.com/en/virtual-clonedrive.html
I hope that helps clear up your confusion a little. If not you can find several related videos on Youtube of how to mount or burn a disk image in Windows. http://www.youtube.com/results?search_q ... 2o9WwBOrRM