Honestly-How is a bed put together?

I am buying a bed frame (sleigh bed) from a local store in my area. I need a mattress and I am kind of confused. This is my first time living on my own and not sure if I need a box spring as well. In all of the pictures, it looks like there is one that comes with them. Could you explain how this works? this is the bed frame we are buying: http://www.biglots.com/p/c/beds/upholstered-queen-sleigh-bed I know I sound ridiculous but I have never done this or asked or paid attention while I was younger and lived at home. Thank you so much. When I search for Matresses it looks like there is a box spring that comes with it. For Example: http://www.biglots.com/p/c/queen-mattresses/serta-perfect-sleeper-ballard-premium-quality-queen-mattress so this is just the matress right??