Compile with TikZ external library

As explained in the pgf manual under 32.4 and in various other questions/comments here on TeX.sX (https://tex.stackexchange.com/a/44508/9077, https://tex.stackexchange.com/a/32363/9077, https://tex.stackexchange.com/a/23565/9077), it's possible to export a TikZ picture as a pdf with document like this:

\documentclass{article}
% main document, called main.tex
\usepackage{tikz}
\usetikzlibrary{external}
\tikzexternalize % activate!
\begin{document}
\begin{tikzpicture}
\node {root}
child {node {left}}
child {node {right}
child {node {child}}
child {node {child}}
};
\end{tikzpicture}
\end{document}


The problem, however, is that neither the manual nor these answers provide any detailed explanation for how to compile this document. I'm using texlive in Windows 7 with TeXworks, so please do not suggest command line compilation procedures.

I need to compile with XeLaTeX since I'm using fontspec. My XeLaTeX compilations look like the following:

What do I need to change to be able to use the external TikZ library?

• You need --shell-escape active. – Qrrbrbirlbel Nov 10 '13 at 20:21
• @Qrrbrbirlbel Yes, the manual and the questions I link to say something of that sort, but I have tried to add --shell-escape in various places, but it never works. Could you (or someone) please provide a complete compilation procedure for XeLaTeX? – Sverre Nov 11 '13 at 11:32
• xelatex --shell-escape --synctex <filename> should do. However, you also need to setup external to use XeLaTeX, especially if the preamble uses XeLaTeX-specific stuff, the /tikz/external/system call needs to be setup correctly. – Qrrbrbirlbel Nov 11 '13 at 19:13
• @Qrrbrbirlbel 1. The inclusion of <filename> there indicates to me that this is a command line interface? I don't use the command line, so I wondering (as indicated in my question) what I need to include in TeXworks compilation. 2. I'm sure I need to set up external correctly, but I have no idea how to do that ... – Sverre Nov 11 '13 at 19:46
• @Sverre please see here: tex.stackexchange.com/questions/82699/… – Paul Gessler Mar 2 '14 at 14:23

With the help of Paul Gessler's link to How to enable shell-escape in TeXworks?, --shell-escape can be added to the XeLaTeX compilation in TeXworks like this:
Running the MWE in the original question, the compiler will compile a separate file main-figure0.pdf with only the TikZ figure, in addition to the full document main.pdf: