@helpmeplease welcome to the KNIME forum. I am not sure there is a consistent introduction about the Continental nodes. I have not done much with them but it seems you have to grasp the concept of this “control table” it seems.
https://www.knime.com/community/continental-nodes-for-knime-xls-formatter
Then there is the free book “From Excel to KNIME” which also has a chapter about Continental nodes. This also might be a good pint to start understanding the concept.
the book is also available in other languages like German, Spanish and Portuguese:
Another overview about what is possible:
Then there is this collection of tutorials:
And there is an older FAQ
https://www.knime.com/community/continental-nodes-for-knime-faq