I tried adding a Questions button from a template and that does not work.
I also tried to add Questions content in a content-by-label macro and it did not display.
Are you using Questions in Confluence Cloud or Confluence Server? There are some differences (see this blogpost).
There is a Questions List macro that is very useful to show questions content by topic (that is the best way to show Questions content). You can vote and watch the following feature request: https://jira.atlassian.com/browse/CONFSERVER-47087
Where are you stuck with adding a Questions macro to "Create a question"?