[ns] compiling same file names like ll.cc and packet.h

[Safiya Nureen]

if i have a separate model that already have been done with all necessary files like .cc, .h .tcl , in a new folder . and i need to compile and check.
but i am little bit confused , like this model have also varp.cc (modified) and in ns2 main directory their is also another varp.cc , 
so if this happens then how to compile with little confusion.? should i replace file or ...?
thanks

Safiya
King Faisal Univ.
Saudi Arabia