how do i turn on the default newbb flat mode?
i set it in system admin-> perference-> comment ->

Default Comment Display Mode : Flat
Default Comments Display Order :Newest first

But anonymous users .. when they read the forum..
its in Nested Mode


Also..
is there anyway to disable users from flooding in newbb
like these :

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Can't help you with flooding but your questions about flat mode should be covered here...

https://xoops.org/modules/newbb/viewtopic.php?topic_id=17191&forum=17

The current version of newBB does not have any flood protection enabled. I'd recommend adding a feature request to the newBB Development Project