Fly out main menu / navigation

[Tonyt8]

Support Typo3 12.4.9 / Bootstrap package 14.0.7 / PHP 8.2.14

I would like to convert the 3 level mega menu to a fly out menu something similar to t3bootstrap v5.

How can I change the Bootstrap_package 3 level mega menu into a fly out menu. I don't know where to start.
Can it be done by only adding CSS or are scripts required as well?
If yes is there any existing CSS change the mega menu to a fly out menu?

Thanks.