To create a weapon do the following:
  1. 1.
    Open the creation tool (Tools -> USK -> Create -> Weapon)
  2. 2.
    Set there a weapon model and press the Create button
  3. 3.
    Add all required animations to the WeaponController component
  4. 4.
    Adjust the Attack Point
  5. 5.
    Adjust the weapon collider
  6. 6.
    Customize other parameters you need

The next step is to adjust the weapon to match your characters.