Grab the SphericalHTM_3_1_2.zip, and unpack it somewhere. Follow the instructions in ./local/README.txt.
The directory structure after installation
C:\apps\jhucas\bin\Release
    Spherical.Quickhull.dll
    SphericalHTM.dll
    SphericalLib.dll
The data files are only needed, if you want to install the data to perform the exercises in the "Table Valued Functions" paper, and in the HTM Primer/Queries
C:\apps\jhucas\data
    PlaceC.dat
    StationsC.dat