How to install:  Take the .tom file and put it in your graphics/wads folder 
and overwrite the original.

2: Place the script, english, and strings files in:

C:\Program Files\Core Design\trle

3: Run the Level convertor and select catacombs.tom   

4: Start up the Tomb Raider 4 that came with the level editor and 
select Catacombs at the title screen