If you know how to make a new project then you will understand how to edit one.

Choose Project - New in the main menu.
You will see the Project New and Edit screen:

Best is to follow the following sequence. A guide to create a new project: If you want to re-edit or view the project, then just choose Project - Edit in the main menu, select the smd-file and you will see that the same screen as for a new project will appear, but with the previously saved info already filled in... .