To install it, all you need to do is to put the files from the zip into the TS directory, then start the game with the 'Dawn.exe'. 

If you are using TS from the "The First Decade", first Drag & Drop the dawn.exe onto the "tfd_ts203modfix.exe" to make the mod TFD-compatible.

To uninstall, simply remove the files.
That should be:

Dawn.exe
tfd_ts203modfix.exe
LangRotD.dll
DWN.INI
rotdxp02.mix
rotdxp03.mix
rotdxp04.mix
themes.mix
ROTDCD01.mix
ROTDCD02.mix
mapr01.mix
videos01.mix
ROTD_README.txt
ROTD_CHANGELOG.txt
ROTD_INSTALLATION.txt (this file)

NOTE: It is NECESSARY that you remove any previous version of RotD from the TS folder before you install this version!