This app seems to be a basic implementation of an ffmpeg-based video converter, coupled with basic CD/DVD burning software, that can use the included copy of the Linux app, DVDAuthor, to put video & audio files into a very basic DVD layout that should work in DVD players once burned to disc. Amazing DVD Creator doesn't do anything in the way of menus, let alone advanced features, so it's just sort of a bare bones way to get video files playing using a set top or stand-alone DVD player. It will take a DVD ISO or folder and convert the files, like the usual video converter app, but without the settings those converters normally provide. Of course to create an ISO or folder set on your hard drive from a retail video DVD you'll need software to decrypt that DVD first, & lots of those DVD decrypting apps come with their own converter.
That said, IMHO ffmpeg is about the worst software for creating the DVD-spec mpg2 you'll need. Add that DVDs are somewhat complicated, and that the official specs are unavailable except to a select relative few that paid thousands for licensing. A bare minimum to do a decent job is a decent encoder, e.g. Mainconcept's, and you would *probably* benefit from an authoring app that did not use DVDAuthor. Though it works, it was developed via reverse engineering, and produces slightly unorthodox DVDs, which may or may not play correctly where you want them to. At least consider something like the free DVD Styler for the authoring part. If you can find Nero Ultimate on sale, it's a better route, though there are plenty of other good DVD authoring apps available. I don't recommend re-encoding video DVDs that are anywhere near current... Since Blu-ray, Hollywood has felt no need to provide quality on any video DVD, and in fact ensures that the video on them is too poor a quality to survive re-encoding, because they don't want you to re-encode the DVDs they sell. If you want/need good quality at DVD frame sizes, re-encode Blu-ray or screen-capped 1080p.
Installing Amazing DVD Creator adds the program's folder plus a folder in Users\ [UserName]\ AppData\ Local\. Registry entries are minimal, with one key for uninstall, 2 for the app, & one key when the app's registered or activated.