So I found the problem - the grading script is apparently looking for the order that things are applied, and to apply the template at creation requires you to click the add template under additional actions first, before you enter any of the other information - strange.
I’ve run through this twice, the second time entirely in the order given in the assessment, and I’m getting this error, even though the entity is in my entities list, has an ID of 1000 and has all the data given in the prompt. I also tried applying the new content template in an earlier attempt in case that was the problem, but that didn’t work either - any ideas on what I need to do to fix this and move on?