First, make sure that you are in the text editing window, not the visual editor. If you paste the code into the visual editor, you will only see the code displayed as text.
Additionally, Wordpress has an issue with sometimes stripping code from embedded HTML. To get around this issue, simply install this plugin and follow its instructions: https://wordpress.org/plugins/raw-html/
To learn how to embed your experience into your Wordpress post or page, click here.