How do I turn existing pages into wikis, and why is my discussion page blank?

Hi, I just have a couple of questions:

1) How can I turn an existing post or page into a wiki, as stated in the very plugin description? I am able to find two custom fields, one of which is called "incsub_wiki_privileges", but which values do I provide to make it work?

2) Secondly, would anyone know why the discussion page here is blank: - I have updated to the latest version of the plugin, but it was like this before too.

Thanks for your time!
- Kristian