Assembly Design > Using Assembly > Creating Components > Creating Subassemblies > Locate Datums Methods
  
Locate Datums Methods
Select references from the assembly using one of the following methods:
Click Three planes and OK, and select three orthogonal datum planes from the assembly to which the default datum planes of the newly created component will be assembled.
Click Axis normal to plane and OK, and select a single datum plane and an axis that is normal to it. The system then creates a new component with a datum plane and an axis which it uses to place the new component with respect to the rest of the assembly.
Click Align csys to csys and OK, and select a coordinate system in the top-level assembly. The system then creates a new component with a default coordinate system and default datum planes which it uses to place the new component relative to the rest of the assembly.