Q&A mainly needs a specification by yourself, e.g. is it about a question and a ranking of answers with the possibility to up/down vote replies, similar to stack overflow.
Or are you going the route of a gentle discussion with replies, and let the OP select an answer which solves the topic. The answer should then be highlighted on top, for anyone out there looking into the same again.
I’ve installed this plugin on two instances as default, and users love it.
You could also think of wiki entries, where users are encouraged to document answers to questions, collected for specific topics. Mainly a self-writing FAQ community (in theory, reality proves the rule that not many write docs or howtos). Discourse also allows for that already. You can write entire howtos and whitepapers just with the help of Markdown and HTML. If you do so already on GitHub, it is a breeze. If not, ensure to provide Markdown hints for your users in your FAQ/guides.
https://monitoring-portal.org/t/topic-editing-hints-with-markdown/1070
And yet again, it also depends on your community. If you have many users who just jump onto your forum for their one and only question, you’ll lose them afterwards. Probably you’ll need some things to make them stay, some of them are already inside Discourse with the badge reward system, or the shiny discobot tutorial. Once users get the good feeling on helping others and becoming part of a community, even the boring Q&A game can become an interesting conversation from time to time 