Download

Download Jasmine GJS version 2.6.4:
Source Code • Linux Packages

Jasmine GJS requires a relatively recent version of GJS: version 1.58 or later. That is, at least GNOME 3.32, which you can get on Fedora 30, Ubuntu 19.04, OpenSUSE 15.2, Debian Bullseye, or many other Linux distributions.

Documentation

All your questions will be answered on the documentation page.