You only see the checkbox to mark an answer as the solution if you created the topic.
We don’t have a lot of topics with a post marked as solved yet as the plugin was just introduced today, but here is an example:
We have wiki topics/posts that often function as a how-to guide where everyone can contribute to find the best solution. For very long topics there is the “summarize” function, which will only display the most “liked” and replied-to posts, as these are often the ones containing the most helpful information. Also for some long topics we copied the most important tips and workarounds in the first post.
The forum population ranges from very to not at all tech savvy and that is sometimes reflected in the language, but you can always ask for a better explanation if you don’t understand what someone has written. Usually someone will explain it to you quite fast.