At the moment, Sitix has no prebuilt binaries; I hope to include RPM/DEB packages in the next release.
To install it, you'll need to clone the Github repository, run
./build.sh, and (assuming the build completes successfully)
copy the generated sitix binary to some PATH-accessible location (/usr/bin is a good bet). Sitix requires a C++20-compatible
G++ (usually included with the gcc package); it has no other dependencies. Sitix is theoretically cross-compilable to Windows, but I have no intention of ever officially supporting it;
Microsoft doesn't deserve it.