There are two types of spoilers. One that shows a black bar hiding the goodies. Click on it and the goodies appear. Have a cookie! This one can be placed in-line.
The other lets you title your spoilers. It's the one with the = sign in it. Put your title after the = sign.
This one lets you reveal and then obsure the spoiler. This one appears on a separate line entirely. Kinda like a quote does.
Then there's spoilers inside spoilers.
Just use another spoiler tag inside the original. Up to 5 nested spoilers are allowed. (this number can be changed if we really need it)