The Owler
Living Tree
Move your mouse to the three dots with the downwards arrow labeled 'Insert'. Click it, then scroll down to 'Spoiler'. Click that, and you should get something like this:
Click between the two square brackets ][ on the right, and press Enter. Now type whatever you want into the spoiler.
Example:
Format:
[SPOILER="Insert Spoiler Title Here"][/SPOILER]
Click between the two square brackets ][ on the right, and press Enter. Now type whatever you want into the spoiler.
Example:
Indeed it is.
Format:
[SPOILER="This is a spoiler."]
Indeed it is.
[/SPOILER]