ok well u can use the wand tool or quick selection tool to select yourself then what u wanna do after u have your body selected is , go to the bottom of your layer tab and press the layer mask button. that should automatically erase the background but know its still there just the layer mask makes everything colored in black transparent and everything brushed white is visible. then u can put your back ground it...well or take the layer onto a new document that has the background u want. if you need more help let me know ill try to continue helping out.