Creating full-bleed stories often requires you to overlay text on images. This might not always work out well - unless you spend a good amount of time looking for the a photo that works out well. 

The Overlay feature allows you to add a solid or gradient layer in between your background image and the text layers on top. Here's a a before and after example:
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How to access: Click the Colours & Typography button in the left-side menu then select the Overlay option from the drop-down menu at the top

Make sure the image on top of which you wish to add an overlay is set as Background:

Please note that there are two types of overlays: Solid and Gradient - see below: 

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