You can download MassOS now, to try it out and/or install it on your PC.
All releases of MassOS can be downloaded from the GitHub releases page. From there you can also verify your download against the SHA256 checksums and look at the release notes.
After downloading, please read the installation guide for information on how to create a bootable USB flash drive for trying/installing MassOS.
There are 3 possible download files, which one should I pick?
For the majority of users, you should grab the standard ISO, labelled "massos-VERSION-x86_64.iso". Choose this if you unsure.
The alternative "-nofirmware" ISO, which contains no proprietary firmware, should only be chosen if you know your hardware doesn't depend on the firmware.
Finally, there is the Rootfs tarball (.tar.xz file). This is designed for advanced users who want to manually install MassOS.