To add your custom assets, head over to your project admin page and click the "Add Content" button:
In the WYSIWG Content box that appears, click the "Source" button:
In the source editor, paste your custom code. The editor offers full support for embedded scripts, iFrames, style blocks, and HTML:
Click "OK" and remember to save your content block and drag/drop in the location you'd like. Your content will now appear on the live survey.
Pro tip - we recommend checking out http://embedresponsively.com for help formatting your custom content for multiple device widths.