Hi @asmartin and welcome to the Canvas Community! I may be misunderstanding your question so please let us know if this doesn't provide the answer you need.
If you have taught a course in the past and are teaching it again, the best way to move content into the new course is by copying the content of that course as described here, How do I copy content from another Canvas course using the Course Import tool?. This duplicates the previous course into the new class shell. There is an option to update events and due dates. If this option is not utilized the dates from the previous course will be used and then the instructor can change these as appropriate.
If you wish to export a course, you can do so using the directions in this guide page, https://community.canvaslms.com/docs/DOC-12785-415241323
I hope this helps and best wishes!
Thanks Eric. I think I figured it out. I read the course import tool but was trying to export the course, make changes and import it. I somehow missed that you can choose a different semester and all was automatically changed. And I was drawing from several sources. The lion's share is done. Thanks for the quick response.