Which Mac download should I pick, and what happens if I pick the wrong one?

There are two Mac downloads: the file with "arm64" in its name is for Apple Silicon Macs (Apple M1, M2, M3, M4), and the file without "arm64" is for Intel Macs. To see which one you have, click the Apple menu, then "About This Mac". The Apple Silicon build does not open on an Intel Mac. The Intel build runs on an Apple Silicon Mac through Apple's translation layer, but it is slower and its audio engine may not work, so always use the arm64 file on an Apple Silicon Mac.