OK, be prepared.
1) Download the latest "Lite" (only a few music tracks) of "Full" (all music) version of ROTD.
1.1) If there is a patch with a higher version number than the full version has, download it as well.
2) Now extract the downloaded "lite" or "full" version into any EMPTY folder of your choice. ROTD is completely stand-alone. Do NOT! put it into an existing TS installation.
2.1) If you have downloaded a patch as well, extract it into the same folder. If you're asked wether to overwrite an existing file, do so.
3) double-click the RTD.exe inside the folder to launch the mod.