How Do I edit an existing product?

Your question is a broad one and the answer depends on what your objective is.

To make minor changes to an existing symbol - e.g. to edit a text field or delete/move something in a symbol - you can use the Unlock Cursor.

To add something or make radical changes, or to create whole new products and symbols, you should create a User Defined Product (UDP) and potentially use the Symbol Editor (rightclick on the UDP in the Product Browser and select Edit Symbols).

The Movie "Adding New Products" covers many of the techniques you should find useful, as does the online Help system.

I hope this is useful.

Kind regards,
Rob Robinson
Stardraw.com