Config files: Fltsim.XX Replace the XX's with a number. ??

   I,m sorry if I sound like a dummy, I'm an old senior that enjoys flying. I don't understand that replacing the x's with the next number means. Would someone pleas help me and explain exactly what i'm supposeed to do.This has kept me from installing acft in fltsim X. Example: {Fltsim.XX} change the XX's to the next number and place  it above it.  What number does it mean ?   Thank you.. I'l be looking for the answere.    John