Create editable mailchimp template (html format)

We require a mailchimp template, that has the colour coordination and part of the header and footer of our current campaigns ([login to view URL]) including the two sentences at the very top, but a new layout (see attached drawing) for the body. Mailchimp templates are written in html and then can be uploaded into the software. The text and image boxes shown in this layout have to be editable, so that we can change them for future campaigns to our customers. If you have not worked with mailchimo templates before you might want to make sure that you can do it (just a comment from my past experience with freelancer)