When you've created a prototype, or if you've changed the design of something that you've set up in your Hololink, you don't need to add the correct position, animations and actions to the new asset.
Simply replace the existing asset with the new one, and everythin will still be set up the way you want it.
For example, if you want this astronaut with the apple head, to have an avocado head, you just:
Click on the three dot menu in the upper right hand corner
Chooses replace
Choose which 3D object you want to replace the apple with
It as easy as that.