Hi,
in order to delete a project, please close the one you wish to erase by creating a new one under the MEDIA section.
Now you can select the one to erase and tap on the trash/delete button to your left. That will move the project to the trash folder. Now open the trash folder and any projects you want to delete will be visible in the list.
Hold the trash/delete button until you see the “Empty the trash” pop up.
Please also have a look at our Cubasis user guide:
http://www.steinberg.net/fileadmin/files/PRODUCTS/Apps/Cubasis/Cubasis_Help/Index.html
Greetings
RG