Issue with adding questons and problem with text editor

Hi,

First of all I would like to thank you for this greate plugi in.

I was struggling with few issues and gave up therfore I hope you will be ale to help me.

1. URLs-
   My idea is to have the following url structure:
   https://pozyczasz.pl
   this should be subpage with topic list
   https://pozyczasz.pl/forum/my-question-title
   this should be subpage with single post
   https://pozyczasz.pl/forum/question/
   this should be subpage with “add qustion” subpage
   I have settings as on the screenshot:and have 404 error when trying add new topic.
   I’ve noticed that issue doesn’t exist when I chage url with topic list, for example https://pozyczasz.pl/forum-1
2. How to disable text editor? My goal is that visitor has possibility only write text.