There's an option in the [Settings] above where users can turn "Always noko" on or off

Personally, I only enable it when dumping - Heyuri is slow enough that I won't immediately lose a thread halfway down the index after posting, plus I think it's better to feel like I'm posting to the board rather than posting to a thread

The latter can make threads feel like they're mini-boards/chat rooms in and of themselves, which changes the whole dynamic and lessens the cohesiveness of the board