How do you get them to only spoil a certain part of the post instead of everything below it?

Is there a help button somewhere I am missing for code information?

I have the same question, cant seem to find a faq or any information here

Because I forget often enough and so the answer can be found somewhere:

I can't seem to get this to work. Is HTML the right language to use, or did the syntax change recently?

Edit: OK I got it to work. I was thinking you needed to add a section of code, which you do not. The ender did not work for me though. It still hid everything below the opener.