Adding a Mod? Question

[Doobie]

Hey I am new to the modding scene, just downloaded Tekkit. I dont want to start building stuff inside if I cant add my own mods to it down the line. Here is my folder structure, can I add mods to this down the line or is it not possible?

 

 

I imagine I can just add my mod to the mods folder?

Also what do I need to add my mod to this?  http://files.minecraftforge.net/maven/net/minecraftforge/forge/index_1.6.4.html

+ and IDE and im good to go correct?

[Animefan8888]

1.6.4 can no longer be modded for and is no longer supported by forge.