The latest releases will always be available on the Sourceforge download page along with release notes describing what has changed. Just find the latest release and click the "Download" link by the "mrbs" package like this :
Alternatively you can get MRBS from the GitHub repository. Releases are currently made from the 'main' branch.
$ git clone https://github.com/meeting-room-booking-system/mrbs-code.git
For installation instructions please refer to a file called "INSTALL" in the release/repository that you download.