Paste the URL that you want the corresponding box to link to in the "Page URL" column. The URL of the box will be replaced at runtime. When a user clicks on the image or the title, they will be taken to that page. To change an image, right click on the image you want to change and select "change image" from the popout context menu. Make sure all of the images for all of the boxes are the same size. They will be fit to 100% width of the container.