1- First, here is how to install mods in Deus Ex Human Revolution :
2 - Now for thoses who want to create mods for this amazing game, you need to extract the game's files. And for this, you need the Gibbed Tools.
3 - If you want to modify a mod (like adding or removing functionalities, you also need to learn how to extract the files inside the mod archive and then you need to learn how to rebuild them properly. This video explains just that :
4 - How to add (or remove) files from a mod for Deus Ex Human Revolution. For thoses who would like to add more files to a mod archive so they can create a customized mod for themselves, here is how to procceed, in video :