View available stickers: Stickers
To add a sticker, create a stickerpack thread using the title as a pack name, and a tripcode to own the pack. Then, add posts with title as a sticker name, and the same tripcode, to the thread. Their attachments would become stickers.
[post]123[/post] — Link to a post
You can try pasting the text and previewing the result here: Preview