This is just a set of pointers to the most useful parts (for me) of the Wix tutorial. I’m calling out the FireGiant domain as these guys are the owners of Wix (It’s late – I know what I mean), and therefore to distinguish from other tutorials.
Your starting point is here.
Putting it to Use references a basic set of files (SampleFirst archive link).
First Steps goes into UI and gives a more complex structure using the same source files (SampleWixUI link). These are dummy files – don’t expect them to work.
Here is a DotNetRocks show with Rob Mensching, who I understand is the leader of the WiX project under Microsoft. (may have that wrong)