the README files for the packages will provide some information on installation and initial use. See packages/cli, packages/web, packages/desktop
the currently available application (www.openjscad.org) is on the master branch. and there is major development on V2 branch.
we are asking for people to become 'early adopters' if interested in V2. there's been some good progress lately with the creation of the initial v2 packages. more to come in the next few weeks.