Couple of things to rectify small or big mistakes.
When entering information in the text box Ctlr+z will undo.
Want to go back to a previous version of a page, click on page history and restore back.
Want to wipe out everything you have done in a course, go to Settings and click Reset Course content from the menu on the right.
Need assistance, contact this office, check the Canvas tutorials, Canvas 24/7 help and Canvas Commons for ECU templates.