On this video Bob Gager, Group Product Manager for Photoshop Elements, demonstrates how you can change backgrounds in your photos in Photoshop Elements using a layer mask.
What you need to know if you want to change or remove the background in your image is that you will need to select either the things that you want to keep or the stuff that you want to remove from your picture and do a good selection (so you want be left with some background that you don’t want).
To do this Gager uses the quick selection tool to select only the objects he wants to keep by using the add (you can also subtract by holding the alt key on PC or Option on MAC). If the selection is harder you might want to zoom in and make sure that you actually select only the stuff that you want (use a small brush to do this selection). If the quick selection tool fails in a problematic area you can try the selection tool (found on the right of it at the bottom of the screen).
After you finish making your selection press on the add a layer mask and we are left with only everything that we selected and everything else is gone. In this stage you can use the paint brush and everything you brush with white and you draw it will be shown and if you choose black it is erased (this is a way to fine-tune your selection).
We have looked at changing backgrounds in Photoshop many times in the past (the process is quite similar actually although Photoshop obviously has many more options). You can check it out here (it has a few more videos on working and changing background in Photoshop as well).
You can find more Photoshop Elements guides on our dedicated photo editing section on LensVid.