1) Once you extract the zip file, copy the 'air' file.
2) go to your fsx main directory/simObjects/airplanes and locate the concorde folder
3) Look for the file 'concorde' its an 'AIR' file extention.
4) now paste the file you copied at the biginning and it will tell you to replace the one in there. do it! 

and there you go. iv tried to make it simple. hope it helps.
