Download the tarballs for all the projects and untar them in the root folder of this project (I recommend 7zip to do this). The library versions you need are the following:
- fribidi-0.19.7
- freetype-2.6.1
- libass-0.13.0
- harfbuzz-1.0.4
Make sure yasm.exe is in your path for asm optimizations.
Now open libass.sln and you should be able to compile all 3 projects.