If you're new to Creator, you might want to use the BiblioBoard Creator Toolkit. This toolkit provides you with 6 files, one per media type, and prompts you to search for two additional content pieces. Then, the Toolkit guides you through each phase of Creator, teaching you how to do each step. It takes about an hour and a half to go through the Toolkit and at the end, you have a practice Anthology for you to review and share with colleagues.
Of course, you can feel free to disregard the content provided for you in the Toolkit and instead use your own content. BiblioBoard will not publish any practice Anthologies, so you do not need to worry. Sometimes, practice Anthologies made of your own content are helpful for your coworkers to understand how BiblioBoard would be helpful for your organization.
Download the toolkit here.