If you don't have any photo editing program yet,you can only print those PNG files out and use them for traditional paper scrapbooking.To use them the regular way you should have
Photoshop,Paint Shop Pro or Digital Image Pro or any special scrapbooking software like Scrapbook Factory.This way you can make your layouts completely digitally putting downloaded papers and embellishments together with your photos and printing out the finished picture.Find out how it works reading tutorials for beginners (button on the top of this page) and start soon.