First, you need to know that dummy has 2 types; Caster and Visual
For Standard Dummy;
Art - Shadow Image (Unit): NONE
Combat - Attacks Enabled: None
Combat - Death Type: Can't raise, Does not decay
Movement - Type: Fly
Pathing - Collision Size: 0.00
Stats - Food Cost: 0
Stats - Hide Minimap Display: True
Stats - Unit Classification: Nothing
For Caster Dummy;
Art - Model File: _.mdl (Shift-click this field and enter "_" without the quote)
Art - Animation - Cast Backswing: 0.00
Art - Animation - Cast Point: 0.00
Movement - Speed Base: 0
For Visual Dummy;
Art - Model File: Select any model you wish
Movement - Height: The height of your dummy from the ground (if this dummy becomes a projectile/missile, it needs height to look "logic"
Movement - Speed Base: Greater than 0
The meaning of "Standard Dummy" is that both of the dummy type must have that field settings.