How to Tweak Custom made Factory Weapons!??

[Lavis]

Please I have been wanting to make a weapon in the Weapons Factory then Tweak it but I have no idea how to do that. I have kinda tweaked around before and learned some stuff in Local and in weapontweak folder.

I am curious is there steps involved?
I hope i made this easy to understand.

So I need answered:
1) How to tweak a factory custom made weapon that I personally made.
Thanks for any help!