Short answer, you can’t, you can’t, you can’t. AARI is not a responsive web form tool; it is as basic as one can get. For each of your questions:

      #1 You can add an image to the form (but not background, and you cannot overlay another object)

      #2 You can enter very simple text in a field

      #3 

If you would like something better, both visually and functionally, take a look at PixieBrix. You can build forms directly into a web app’s page, elements take on the look and feel of the html around them so it is transparent to the end user, and you can use them to call automation just like you would with AARI. Plus, the user can stay in one screen instead of bouncing back and forth.