(There's no video for macOS/OSX Server 5.x (app) yet. Please contribute to MR and add a video now!)
The macOS Server app was downloadable from the App Store until Apple discontinued it on April 21st, 2022. Here, in this archive, are some of the versions that could be salvaged from the internet before it's completely erased for good!
Note: Please use caution and back up your files on your Mac before installing those apps (just in case) because bthey come from unknown sources.
(71.52 MiB / 75 MB)
macOS Server v5.12.2, requires macOS 12.0 or newer (2022-03) / DMG image, zipped
(74.56 MiB / 78.18 MB)
macOS Server v5.11, requires macOS 10.15 or newer (2020-12) / DMG image, zipped
(184.71 MiB / 193.69 MB)
macOS Server v5.4, requires OSX 10.13 or newer (2017-09) / DMG image, zipped
(207.09 MiB / 217.15 MB)
macOS Server v5.2, requires OSX 10.11.6 or newer (2016-09) / Zipped
(202.64 MiB / 212.48 MB)
macOS Server v5.1.7, requires OSX 10.10 or newer (2016-07) / DMG image, zipped
Architecture: Intel x86
Mac OS X 10.7 - Mac OS X 12.6 (depends on the version, refer to the downloads list)
Emulating this? It could probably run under: QEMU