Glad to hear you got it installed! And thanks for testing and providing feedback.
> I have noticed that this character does not produce: ☎, does it mean that Unicode is not supported, or I maybe lack some fonts?
PDF is a "bring your own font" format. We try to provide fonts that cover as many glyphs as possible, but there are few fonts in the world that provide every glyph, and those that do aren't very appealing. So Asciidoctor PDF provides a way to add more or replace the ones provided.