1) An injector is a program that injects a "dll file" into a game.
2) Yes you use the injecter with the hack.
3) Doesn't matter where you live, a working injector will work for ca. Not sure what CP is
4) The injector is in a winRAR file because a "rar" file compresses a file so its smaller. If you want to open it download the program "winrar" its free and useful.
5) When someone says a software is leeched, it means that they have taken that program from Another forum and posted it on this forum.
Of course i could of answered this with more detail but I'm lazy. If you have anymore questions ask.