We just set up 3 workstations if you don't mind waiting a couple of days we can go in on Monday and share the directions we followed. Maybe that will help spell out how we can improve the documentation as well.
With pgAdmin4 version 1.6, we have changed the way we bundle and serve the javascript and other static files. Refer steps in this email thread, if you want to use it from git repository, Another way is to download and use the source which is already bundled from here