It's super easy to create an embeddable note-card, just create a share code and copy the embed from within the share dropdown. Here's a quick walkthrough below:
Open the share dropdown and then click "Create new code". Make sure 'Publicly Viewable' is turned on and then 'Generate Code'. Finally hit the 'Embed' button to copy the embed code.
If you would like to see some great use cases of embeddable cards, have a read of this article on our blog.