Platform requirements

examples/_mu/README.md

@@ -4,10 +4,11 @@ This is an experiment. So far, it's nearly but not quite working.
 
 To build the MSI package:
 
-1. Run `pynsist installer.cfg --no-makensis` to assemble the necessary files. (If necessary, `pip install pynsist`)
-2. Run `prep_files.py` in this folder to move some files and call 'heat' to
+1. You need a Windows machine with [Wix](http://wixtoolset.org/) and Python installed.
+2. Run `pynsist installer.cfg --no-makensis` to assemble the necessary files. (If necessary, `pip install pynsist`)
+3. Run `prep_files.py` in this folder to move some files and call 'heat' to
    make a list of the files.
-3. Run `wixit.py` in this folder to build the msi package.
+4. Run `wixit.py` in this folder to build the msi package.
 
 ## Resources