I've documented the steps on the GitHub wiki. What the docs don't say, is that there is a problem when you're using Qbs 1.8, so make sure you're using 1.7 for now.
The installers are built with VS 2013. I have not tried VS 2015, but they may work. You'll likely need to make sure to ship other versions of the VS runtime, though.
Note that an easy way to get an installer is also to open a pull request, since AppVeyor builds pull requests and hosts the resulting installers under Artifacts.