I was wondering what is the placeholder for the second and third author?
I understand that under compile metadata menu – authors section, I add semicolen to separate authors but when compiling via (latex) I can’t output second or third author since the only placeholder I found is <$author> which references the first author only.
any help is appreciated!
Do you need multi-author listings for anything in particular? If not, I’d just work around the design of the field by typing in the authors in such a way that they all are enclosed in the same “bubble”. For example: “Author One, Author Two, Author Three”, works fine, and will print in the LaTeX output just like you typed it in. It looks a bit silly, but it works. 
Alternatively, if you don’t need the <$author> tag itself for anything else, you could just type what you need directly rather than using the GUI field. For MultiMarkdown conversion, you’d type it into the Author metadata field below. For LaTeX, it would probably be typed somewhere into the front matter text in the binder.
Thank you got the reply, it is very helpful!
Yes I was hoping to reference the authors in another place in the output tex file. Also, I was hoping finally to get a fully working IEEETran template ready for upcoming research papers. I love working with scrivener and I have had difficulty before going from it to latex but it seems now its very straightforward.
I will try to put all the authors on one bubble but thought since the bubbles were there in the first place to separate authors that it might have some sort of a placeholder reference for them.
I appreciate your feedback!
As I recall, the only export type that makes use of actual multiple authors as discrete entities are ebooks. So the bubble effect can be entirely ignored unless working with ePub.
Glad to hear things are working out well for the setup!
each author name has a latex code attached for his/her ORCID ID and that means each author name is a long line. I ended up using the <$author>, <$forename>, and <$surname> placeholders for each author so that first author code was under <$author> and second author was under <$forename> etc.
As a more robust alternative, this can be approached using some of the Pandoc academic templates with a front-matter document in Scrivener. You can see examples for my workflow here, where authors can have affiliations, correspondence addresses, share equal contribution etc. — this is also available using pandoc-scholar…