Aero/the Funnel Builder Checkout is compatible with MailChimp for WooCommerce plugin available here:
You can follow the steps below to set up MailChimp for the WooCommerce plugin.
Step 1. Please make sure to connect your store with MailChimp.
Step 2. Add or replace WooCommerce action hook with Checkout hook in MailChimp Audience Settings
"wfacp_after_billing_email_field" to display MailChimp opt-in checkbox on Checkout page:
Also, you can follow this video to show MailChimp checkbox on your store Checkout page:
https://www.loom.com/share/40355c1591fa4ac4b1a545fca2d1fe68
Let us know if you stuck anywhere while doing this.