Building a Trell Power Up

I am trying to follow the Atlassian tutorial to build a power up found here:

I follow the step to create the power up in the admin console and I see that my power up is enabled. When I try to add the power up to a card I can see the power up, but there is no add button. I’m not sure what I’m doing wrong and hoping someone can point me in the right direction.

You need to add way more information for any to have any chance to help you. We need code, scenario, setup and so.