I can see that you are new. Search for the mission editor, and check the stickied topics. Also, use a question mark instead of a period ( ? instead of . ) at the end of the title so people know its a question, NOT a stickied tutorial. Also, the mission editor is a client mod that lets you change around maps, and add / delete stuff from them, then save it to package as a map.
if there are no problems with this, you need to lock this topic so it gets old and sinks to the bottom of the forum.
