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