How do I create a spoiler?

Hello.
I have trouble with adding a CMS spoiler.

What I need to do is to add a heading, when pressed it opens a spoler with additional info.
I did it with using a dropdown trigger, but it doesnt really move everything below spoiler. It just shows the spoler element above everything. I can’t find a decision for it.

Help me, please!
Thank you.

The preview link is literally useless in this case. I added it only to not violate any rules of posting.