The Format of a Residue Topology File

The purpose of residue topology files is to store the
information for generating a representation of macromolecule from its sequence.There are two forms, binary module (.MOD) and card format (usually .INP).
The card format files are used only for creating binary modules and therefore are structured as input files for CHARMM, beginning with a run title and the command READ RTF CARD, followed by the actual topology file.

if the protein was solvated with vmd, and you want to run simulation with mmtsb, add "-par boxx=a,boxy=b,boxz=c"