Just unzip this file into the Descent directory. Start Descent as usual 
and start a new game and select Lupis Six as the mission.

к----------------------------------------------П
Г A NEW add-on level for the Registered DescentГ
ГллВВВВББББББББААААААААААААААААААББББББББВВВВллГ
Г                  Lupis6  v 1.0               Г
Г Lupis Six has just been infected by the      Г
Г mutated kin of Lupis Five. Fortunately,      Г
Г the infection is limited -- for now. Be      Г
Г amazed at the new tunneling skill of the     Г
Г heavy drillers! Watch out for those invisibleГ
Г baddies; you just never know where they mightГ
Г show up next. This level is excellent for    Г
Г individual or deathmatch play. Large design  Г
Г and fully multiplayer supported.             Г
ГллВВВВББББББББААААААААААААААААААББББББББВВВВллГ
Г           Created By Brett Russell           Г
Г            (brettr@interramp.com)            Г
Р----------------------------------------------й