From 3ds max to .nif (weapons)?

[Newgamemodder]

Ok so i have searched for about an hour about how to create a custom weapon for fallout 4 but havent found what im looking for.

 

I have a mesh of the weapon i want converted.

 

Now my questions are:

 

1. How do i make mods for it and do i need to detach my mesh into parts? (like barrel, sights etc),

 

2. How would one make custom animations for this? (i know how to make them but not with the parts, or do i need to make the animations with the parts?)

 

 

Is there a video about this?

 

Thanks!