Silverstack Lab has built-in support for opening projects in Drylab Creator 3.

Here's how:

Make sure that you have both Drylab Creator and Silverstack Lab installed on your Mac.
In Silverstack Lab, go to the project you want to open.
Click the Export button and Drylab Creator (XML)…
In the window that appears, click the Open in Creator button on the bottom right.
If the project matches a document that's already open in Creator, it will be imported straight away. If not, Creator will ask you to either open an existing or create a new document.

Export a project from another version of Silverstack

It's also possible to export to Creator from a non-Lab version of Silverstack:

Make sure you select all clips (since you'll only see the ones you've selected in Creator and Viewer).
Click the menu File → Export → Pomfort XML Metadata… and save the XML file to disk.
In Creator (with a document open) click the menu File → Import Silverstack XML… and choose the XML file on disk.

Video tutorial

See also the following video tutorial, which walks you through the process from Silverstack to Drylab Creator and Viewer: