A preliminary copy of the Gforth-0.5.0 manual was here.  You can find
the current version of the manual <a
href="../../forth/gforth/Docs-html/">here</a>; <a
href="../../forth/gforth/Docs-html/gforth.html#Tutorial">Tutorial
anchor</a> (into a 900KB file); <a
href="../../forth/gforth/Docs-html/gforth.html.gz#Tutorial">Tutorial
anchor</a> (into a 200KB gzipped file).