I know there is a video tutorial how to use the MailChimp plugin to bridge between RS Form and MalChimp (link), and how to merge checkbox selections into separate lists on MailChimp.

However I couldn't get it working even after following the video exactly step by step. I did however manage to get it to work and here's what happened and what I did to get around the problems.

The first problem was that the MailChimp menu link did not appear on my Form Properties tab after I entered my API key. It turned out that I must've had older copies of the component or plugin that weren't compatible with each other or something, but the problem went away after I downloaded the latest versions available.

The second problem was that my form submission though was processed fine by RS Form, returned a Failed API Call on MailChimp. You can see this on the API calls summary page below your API numbers and the errors are marked red.

The problem was that I didn't know that with your checkboxes you have to format your selections list like this:where the first part is the value that gets passed to the emails AND to MailChimp, whereas the second part is the label or caption to be displayed on the form itself.

At first I thought it was the other way around, {label} | {value}, but it is NOT.

Next problem was that new registrations were still not added onto MailChimp. I got both Admin and User Emails from RS Form Pro but they were not added onto MailChimp's List.

I found that there was a slight discrepancy with the video tutorial and the latest version MailChimp. On the video, around 5:00 it goes through how you should create the groups in MailChimp. On the video it tells you to create your groups with the following structure:where the Group Titles are used to link to RS Form values and the Group Names are left blank.

However, this did not work for me. This is the structure that works for me:where the Group Title is irrelevant and instead the Group Names (subgroups) are the important ones, and their titles must match the values of the checkboxes. This is how RS Form and MailChimp know where to add the new subscribers.

See image attachment.

I hope this is useful to someone who's struggling with the same issues I had. Hopefully this is clear enough to spare them the hours of frustration and confusion I had.