Making a mod work

[ItchySolid]

Im new to anythin bout modding so could anyone tell me what to do with a rar file to make it work on halo pc?

[MalikDrako]

if u dont have winrar, get it (not sure of the site, search on google)
extract the file
if its a .map file, replace the old one in ur halo/maps folder (backup first)
if its a .ppf file, get ppf-o-matic (look in utilities) patch=the ppf file, orignal=the original map (backup first)