Add clipart images to your photos with the clipart tool. To find this tool, click the Clipart icon on the Creative tab.

Use the panel on the left to select a clipart category. When a category is selected, a list of clipart images will be displayed in the center of the dialog. Click on any image in the list to see a preview on the right side of the dialog.
When you find a clipart image you like, click the Download button. Once the image has finished loading, the clipart image will be added to the project as an Overlay Image layer.