SEO help: Content search words


Well-known member

I was looking for a way to improve the ranking in google for search terms regarding my forums.
When I use google webmaster tools, I can see a page with content search words.

The ranking consists of this:
Screenshot 2014-06-07 23.41.21.png

As you can see, only number 3 and 8 are relevant for my site. All others are "XenForo" keywords that aren't important for me.

So I have these questions:
How can I get more relevant words for my site? What did I do wrong and how to change?