Our teams' SharePoint sites have been migrated from SharePoint 2013 to SharePoint Online and we have received no documentation (and very little training) about how to perform common tasks in this version:
Checking files in and out
The videos we've received for "training" have not been helpful, so we've resorted to creating job aids to help our end users.
Is there anything out there that is free that we can re-purpose, or even better, use as is? Also, is there a differences document available? Something that explains how a task was performed in 2013 vs. in SharePoint Online?
It might be worth considering going back to those responsible for the migration in the first place and seeking clarification, ideally giving them an opportunity to remediate the situation, if appropriate and achievable.
Here is a good start for documentation, some of which you may have come across already: