How to create sticky floating headlines?


I'd like all h2 headlines to float left and stick to the top as long as the related paragraph is being scrolled down. As soon as the next headline is "touched", this next headline should stick to the top.

Everyone will find an example when opening the about.php in his dashboard, w.g.
which is the extended official Welcome-Screen of WP.

Anyboy who could help me with this? I'm not good in CSS, so any help is greatly appreciated :wink:
It would be nice to make this effect available not for all posts or pages, only for specific ones …
Thank you and kind regards,