You insert process steps using the smart menu in the process editor.
Procedure
In the process editor, choose Add Process Step.
Select your required process artifacts or process controls. Sometimes, you get to select again whether to create a new artifact or reuse an existing one. Repeat this step as necessary to continue building your process.
For all steps, the respective creation dialog shows a list of existing artifacts of that type. If the listed artifact stems from dependent project, that project is indicated.
The image is interactive. Click any tile to see how to add the respective process artifact.