Email Solution

I have a couple questions:
1. On the Optin Forms page it says this: Your email solution is not configured yet. Your form will not work properly until you configure the settings.

– It doesn’t tell me what to do to configure my email solution. I’m using mail chimp. I receive emails when new subscribers sign up. Is there anything else I need to do?

2. I’d like the option of putting the optin form UNDER the author bio at the bottom of my posts. There doesn’t seem to be an option for that. As a result, I have it set to “Do not display on posts or custom posts.” I’d like to have it display. Can you tell me if there’s any way to place it below the author bio? Here is a link to a post so you can see what I’m asking: https://opendoorsmorocco.com/odms-bedouin-bivouac/odm-bedouin-bivouac-opening-night/

I’m using firefox and Chrome and my OS is Mac Sierra.