My question was about the steps you are taking on the Body tab, not the steps you take before getting to the body tab.
Once on the body tab, select the HTML Email tab and click the DW Edit Option.
In the editable region, type you any text you would like to appear, where you would form output, go to the bindings tab, expand the form collection and drag the corresponding form element to the page.
Once you are done, go to File save to save your changes and go back to the Universal Email wizard. Once back in the UE wizard, click the OK button, save the page and upload it and the WA_UniversalEmail folder.
These steps should get your email message created successfully.