I was having trouble using the click macro in a story, so I made a little test and it still didn't work, I have no idea what I'm doing wrong.
A goblin attacks you. <<click "fight back">><<append>> You stab the goblin<</append>><</click>>
then I get this notification
Apologies! A technical problem has occurred. You may be able to continue, but some parts may not work properly.
Error: Uncaught Error: <<append>>: no selector specified.
Error: <<append>>: no selector specified
at Function.Object.defineProperties.wikifyEval.value (<anonymous>:41:10936)
at HTMLAnchorElement.<anonymous> (<anonymous>:38:6442)
at HTMLAnchorElement.n.event.dispatch (<anonymous>:7:6444)
at HTMLAnchorElement.r.handle (<anonymous>:7:3219)
You need to tell the append macro to which element on the page you want to append content. The documentation states this: <<append selector>>. Also, the click macro has been deprecated in favor of the link macro. I've amended your code as follows:
Additionally, it may not be obvious, but (a) #goblin does not need to be an "empty" element and (b) #goblin can be position anywhere in the passage. You can put text/images between the semi-colon and the @ symbol in #goblin. The append macro will simply add content to the end of the #goblin element, no matter what else it contains and no matter where the element is located.