The first step is to make sure Avada Forms is connected with your Mailchimp account. See the How To Integrate Mailchimp With Avada Forms document for more information on how to do that.
Once your account is connected, head to the Form Options tab of the form you added your checklist to. Here, under Submission, your will see an Actions option. Select Mailchimp from the dropdown list.
You should then see a Mailchimp option set below this. If you edit this options set, you will see a Mailchimp Action option. Click on Create / Update Contact to continue.
Now, select the Mailchimp list you want to connect to. There are options for Mailchimp Tags, Opt-In preferences, and Form Consent, but the one we want for this document is in the Mailchimp Mapping section. Note how there is a Gardening Experience field. This is the Mailchimp Group we set up on Mailchimp. Click on the dropdown here, and select from the Group Category. In our example, there is onl one, Gardening Experience. This is the Checklist Field we added to the Form.
Now the Checklist on the form will map to the Mailchimp Group of the same name.
Note. If your site is already connected to Mailchimp, and you then add Groups and Tags in Mailchimp, you will have to reset the Mailchimp Cache for them to show up in your Avada Form Options. This is done in the Global Options under Forms > Mailchimp (backend options only).