There is a clone tool in the toolbar if you want to clone areas of an image. And you can find lots of tutorials to use it on the web. This is for copying a portion of a picture into another area of the image.
when in doubt, simply use google enter in the topic or tool you're looking for in the search box & you'll find tons of links for info & tutorials. Same goes for youtube or adobes website. Or, the help section in photoshop