can someone teach me how to get started with a Single Player mission? i know how to make a map now and have a mission idea but i dont know how to make it happen

There is a tutorial on making SP objectives in the CoD tutorial section.

if your talking about the one that says Making a Single Player Map, i went there. do i need a map already done? and what mod program do i use because it doesnt say

No, I mean the tutorial on making objectives.. the stuff you've got to 'do' in your map, as the player.. kill that guy, capture that building etc.
The tutorial will explain you how to do that. But you will need to make a basic map first, because else you've got nothing to test your objectives in. Make a skybox and a ground brush, that's enough to start the tutorial with.

There is only one program for making maps for CoD2 and that's CoD2 Radiant.

II'd suggest making your map first, THEN adding the triggers and scripts and stuff like that.