How do I access the MailChimp power-up in the Beta version?

Question

I am unable to attach a MailChimp campaign to any cards since switching to the latest Beta version. The button is no longer on the card and nothing on the [+Add] menu will attach a campaign, nor does the [Attachment] button. 
I am switching in and out of Beta as a workaround, but it is not ideal.

Allison Weaver_gdn264 · Answer

thank you!!

Gaurav Kataria · Answer

Powerup buttons are now accessible through the bottom island (highlighted below) https://support.atlassian.com/trello/docs/new-card-back/