Re: so frustrating
1. Log in as admin
2. Expand Admin menu and click on Groups
3. Click on key icon beside the group that you want to set permissions to. For example, if you want to provide wiki editing and creating functionality to Anonymous, click the key icon beside that group
4. Scroll down in that page and click on wiki. This shows up the list of permissions pertaining to wiki pages that you can set to the chosen group (as well as other groups).
Screenshot:
I am not sure if you wanted to have anonmyous (non-registered) users or registered (and logged-in) users to be able to create wiki pages. I think by default registered users would be able to do both create and edit so looks like you want anon users to be able to do the same. In that case change tiki_p_edit from registered to anonymous.
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