When you are logged into your dashboard, click on Marketing Resources in the left menu. Assets are in three tabs, Brand Images and Assets, Email Templates, and Social Content. Brand Images and Assets is in three sections, Product Images, Lifestyles, and Logos.
Images have a Download button to download to your computer.
When you click View next to an email template, it populates the window on the bottom right. You can turn off highlights with the "Turn off the highlights before you copy this message:" switch above the content. Then you can click the Copy Text button below the content to copy it to your clipboard. From there you can edit it into your voice. Social Content works the same way.