Self-service DSP Getintent lets you create customized templates for dynamic creatives.
These templates work on Java Script + CSS technology.
To create a new snippet go to the "JS/CSS Snippets" tab
Click the "+ New snippet" button
Then you'll see a JS or CSS redactor
Then you'll see a JS or CSS redactor
See an example of the JS code and CSS styles description for a 240x400 creative tag.
If you want to check a snippet's proper functioning, first set up a dynamic creative: Adding Product Feed and Dynamic Creative settings