How do I introduce a new product to PLM?

If you work on a new large assembly not yet saved to PLM, you can highlight the top model of this assembly in the SolidWorks Feature Manager, and then save the entire structure to PLM. If you complete a component in a large assembly, select this component in the SolidWorks Feature Manager, and perform Save and Unlock.

For further information, see:

Saving and Unlocking Files
Saving Files to PLM