Layouts allow you to create any look and feel to your creative, and to add any event tracking to an ad when it's displayed.
When creating a creative, you will always choose a layout, and your layout will be come visible when you have saved your layout.
Name, description, category and labels: Give the layout a name and description (optional) of your choice. Categories allow you to group layouts with similar traits so that they are easier to find when later booking a line item and creating a creative.
Default width and height (optional): When you add a creative you will always have to provide a width and height to that creative. Creatives using this layout will have these dimensions by default, so that if a creative is usually created with this size, then the process will go quicker. You can of course always change the width and height on a per-creative basis.
Layout type is where you determine whether your new layout will be a third party (to render third-party creative content), HTML (to render HTML creatives that can be uploaded via a zip), VAST 2.0 (to render VAST 2 video creatives), or regular (to define your own components and render template for making a creative.
Layout usage gives you information about the creatives currently using this layout.
Render template is the code that you can insert to determine the look and feel, and any event, of your choice.
Components in render template are assets that you can add to the layout. You can add URLs (for example click destinations), text (for example for native ads), choices (for instance choices on whether a video should autoplay or not), or media (being images in GIF, JPG or PNG).
If you want to change the max file size allowed for a layout, you can easily do so by changing the component, as shown below.
Changing a component's max file size.
The feature is live, documentation will come soon.
Layout examples provides you with a library of layouts that cannot be modified or removed. You can visit each of the layouts, observe its behavior on-screen, and copy it to create a new layout that can be used for your creatives.