There multiple ways to create/add Projects in SIX within the Project Explorer.
The New->From Template feature allows you to create a project based off of a saved template. Click here for details.
To create a Template, simply select an existing Project in the Project Explorer and click the [Template] button:
You will be prompted to name the Template as well as add a description. You can choose whether or not to import any additional files like Visio or AutoCAD drawings. You also have the options of whether to include Work Orders or Tasks from the Project:
The New->Import Project feature allows you to import legacy SI5.5 Projects into SIX. You can import SIX Projects here as well, either ones you've previously exported or Projects you receive from other SIX users outside of your company. This is also how you can import Sample Projects. Click here for details.