Creating sitemap for Question2Answer sitemap is very simple and straight forward. The default installation of Question2Answer comes with several plugins one of which is XML Sitemap.
The version I'm using is Question2Answer V 1.7.2 and it comes with XML Sitemap v1.1.1.
1. Login as Administrator and goto Admin>>plugins
2. Look for "XML Sitemap" usually at the end of plugin list.
3. Click on "options" under the "XML Sitemap"
4. You can select different options here based on which your sitemap will be created. The options I see in my installation are a) Include question pages b) Include user pages c) Include question list for each tag d) Include question list for each category and e) Include category browser.
5. Select one or more options based on your requirement.
6. Click on "Save Changes"
You are done. Your sitemap is now ready.
To access the site map, goto sitemap.xml in the root of your Question2Answer installation.
If your Question2Answer is installed on "example.com", you can access your sitemap at the url "example.com/sitemap.xml"
If your installation is at "example.com/qa" or "qa.example.com", you can access the sitemap at "example.com/qa/sitemap.xml" or "qa.example.com/sitemap.xml" respectively
The sitemap is dynamically generated when the url is accessed. So when you see the contents of your hosting using cpanel or ftp, you will not find the sitemap.xml file. It can only be accessed using the url as it is created on the fly.
(For my site, I have selected only "Include question pages" so that all questions are indexed by search engines. I'm not very sure, but including other options like tags, categories may result in unnecessary indexing and may result in more search results of low quality.)