how can i add them to my module and than to my inventory?

No, -$ilver-, the guns are basically re-flavored slings and crossbows. You can create the items to restrict themselves to certain classes or feats, if you want. If you don't intend to use slings or crossbows, you can write in more tweaks.

Sorry that I haven't really been keeping up with this, but keep in mind that a) I am not the creator and I am not offering support as such, and b) these resources are designed for use in creative content. You will need to be somewhat competent as a builder in order to create or modify a module in which you can use these.

I will definitely try this on another play through. Is there feats or a tech tree to go along with such a weapon or class?

Not sure if it's incompetence, but I can't get these to work.

ahahah, good idea)