K2 V5 Smartforms - Branding

Hi,

I'm very new to smartforms but getting the hang of them. When version 5 came out I'm sure i read that you can now apply branding 'skins' to the smartforms.

I can't find anywhere in the tutorials or in K2 designer where to apply these?   I'm referring to the themeing of the 'Tabs', form background colour etc and not the styling of the fields themseleves.

Thanks for any suggestions, Julie