what? You should just add this following code on the bottom or on the top of you div container: <button class=“btn btn-info” data-target="#demo" data-toggle=“collapse”>
I’ve edited your post for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.
You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.