As long as your device is paired to a printer, you can print from Showcase; from the sharing button in the top right of the app, select 'Print' instead of 'Open with' or 'Share'.
If you can't see this option, you may need to contact your Admin to adjust the sharing settings for the showcase.
The alternative is to email (also using the Showcase sharing feature) the documents / pages to yourself and then print from your computer.
Showcase will print files based on how they've been added. So if there was a document added to a showcase you would have the option to print that entire document. If individual slides had been added then you'd need to print them one by one.
If you yourself are an Admin for the workshop, you can get an overview of the whole showcase on the Outline screen on the app.showcaseworkshop.com website. You can print this webpage from your browser to get a full printed view.