To use the Dynamic Overlays on the MakeMeReach platform, you'll need to be using a catalog. They are available for the App Install and Catalog Sales objectives only.
Once you're in the Campaign Creation flow, in the Creatives step, you'll find lower down in the page a couple of options:
The first option is to enable you to add info on products: it will add a small and colorful indication of the price for each product in your catalog, putting it on top of your picture (and taking the price you have put in your catalog automatically).
Among other things, you can choose the font, position and shape your price will be displayed as:
The second option is enabling you to add a frame to your products, blending it in if you want to! It's a good way to add your logo to your pictures for instance.
You can try any option you want to, leading to results similar to this: