To run, just drop the files in the game directory, mount the drive in DOSBox, then type
setup.exe file NAME.wad
Where “NAME” is the name of the WAD file for the mod you are using (For example, Escape From Totenhaus would be “toten.wad”)
Navigate to Use Modified Stuff, then Choose Alternate Game Levels. Pick the .RTL file of the mod you are opening (For example, “TOTEN.RTL” for Escape from Totenhaus). Go back to the main menu and choose Save and Run ROTT. Enjoy!