Since the game files are in TOS format, I replaced the ROM TOS, so I guess the answer to your question is neither. But I'm really not very competent at messing with Hatari settings and have never worked with TOS files before. Aside from replacing the TOS it runs on the default configuration. Anyway I did get the game running both on C64 and Amiga, so I think I'm good.
Ah, the game is not meant to replace the ROM in the emulator, there are just two executables (for 40 and 80 columns).
You can try to search for an image of an original Atari ROM and OS disk. Hatari will load it and will behave as the original computer with the Atari OS. Usually I configure Hatare so that to have a shared directory on my OS seen as a hard disk inside the emulated computer. The game files are just executables and can be run with a double click. Try also the other games, I remember spending quite some time developing The Queen's Footsteps on the Atari.
Well, I tried setting it up as a file in a folder as hard drive and launch it from inside the emulator, but that just got me a Panic: Illegal Instruction error. But really I don't know what I'm doing. I'm more confident using the Amiga or C64 versions. Is there any difference, e.g. graphics or such between the versions?