@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.
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