Set up on a dCS Vivaldi with NAS

I have a dCS Vivaldi with a NAS. Where do I download Roon? I assume on the ipad. What version do I download on it?

Roon must go on a machine powerful enough to run it, with an X86 processor. If your NAS has enough grunt and is the right make you could run it there. Otherwise it is a PC, Mac or laptop, minimum i3, 4gb RAM. The iPad is for control and endpoint only.