I do not have Photoshop so where do I download it to?
This is a very confusing aspect of the Nik Collection, since it is advertised as a set of plug-ins for Photoshop. Fortunately, it’s like most software programs these days. Just download the software wherever you like (a Downloads folder, your desktop, etc.) and run the installer. I believe it tells you where it is installing the software. You can go to that folder and find subfolders for each tool. Now you can run each executable either by dragging an image file onto it or by exporting an image to the executable from within your preferred image editor. I hope that helps a bit. Hopefully, in the future the tools will be easier to install and use. If that’s what you want from DxO, it would get my vote.