MarkerLayout is included with the package, and it's under tools/ directory. It's mentioned in the User Manual.
The above thread is for you to create individual marker images for ALVAR library.
These images are needed for MarkerLayout program to generate the marker array image.
If you simply want to use single marker for tracking, then you don't need MarkerLayout, and simply use the individual image generated by ALVAR.
Make sure you know which ID is associated with which marker image.