The documentation uses mdBook see the installation guide for further details on installation.
Once mdBook is installed the documentation can be built and viewed with:
mdbook serve --open
# Avoid FuseSoC using copied files in the book directory
touch book/FUSESOC_IGNORE
The second line can be ignored if you aren't building the FPGA bitstream (which uses fusesoc).
On Windows the easiest installation method is to copy the precompiled mdbook.exe
available as a release on the previous link to the sonata-system root directory.
./mdbook.exe serve --open