Having problems with making selections/replacing background? You may want to check this video by George Peirson.
You can use Photoshop Elements selection tools to make a selection that will be used for a layer mask. This will allow us to easily do a background change by cutting the person out of the photo. We will look at the difference between the Lasso Selection Tool and the Polygonal Lasso Selection Tool and I will show you why I would choose one over the other. We will also look at using the Refine Edge tool to clean up the selection.