Creating mobs in tynker

Were having so much trouble getting new mobs made in tynker into our minecraft work

  1. We have a tynker account
  2. When we edit/create a mob for java edition how can we give in behaviours? The editor for PE you can build behaviours. For java there doesnt seem to be any options.
  3. So the mob becomes ‘active’ and gets the little green dot. How do we get this into our minecraft game now???
  4. We are using Java edition
    please help
    Sam & Kate