..found today a bit outdated Apostrophe CMS Screencast (was created about 3 months ago) so it’s pretty possible you’ve already seen them but it was fun for me to look it through (unfortunately still did not have time to dig into Apostrophe CMS).
Apostrophe CMS Screencast
Reordering Images in a Slideshow
Adding Video to Media Section
Linking to a PDF in a Text Slot