Architecting and designing
  
Creating child diagrams and attaching them to symbols
1 Select the parent symbol, to which you want to attach a child diagram, by clicking it one time.
2 Right‑click the symbol and either:
Select Child Create to create a child diagram or select Child Attach to attach the symbol to an existing diagram. If you select Child Attach, the diagram you attach becomes the child of the selected symbol.
or
Select the parent symbol, and then select Child diagram under the Edit Menu. Then, from the secondary submenu under Child, you can select Create to create a new child diagram, or select Attach to actually link the parent, which is the symbol you originally selected, to an existing diagram.
When a symbol is attached to another diagram, the Child Create and Child Attach submenus are automatically modified to become relevant selections: Child Detach and Child Open.