Add Bone Parts For NPCs

Add a new bone part (Bone Parts → Add Bone Part → Name).
Add bones to the created bone part (add by setting the bone weight from 0.0 to 1.0).
Create Params with the same name as the bone part (Window Motions → tab Params).

Via clicking RMB → Add name.
Go to the animation script.
Choose a default process block.
Find a link from the process and insert a filter between two existing blocks.
Captions – name.
Weight Mode – the gesture.
Bones – from the list, select the same bones as you did when creating Bone Parts (you can add locators that don't include the hierarchy for the selected bones).

Don't forget about checkmarks.
Add a param_motion.
Write the name of the prop in the tab Param which was added in Step 3.
Link it.
Save (AS & Model).

Exodus SDK