i. Click on the Add New Button
ii. Start designing Reply Form by drag the content to any row you prefer.
iii. If you want to add the row, you can click on Add New Row button and if you would like to arrange the row, simply drag the row to any position.
iv. To edit/amend the content, double click on the row and the system will open the editor for you to edit the content
If you want to know find out how to add images into your email content, you can refer this article: How to add image into Site/Email/Confirmation/Badge/Invoice Design?