whey is a protein that is quickly absorbed (alternate to casein, which takes longer for the body to absorb). of course there is a more complicated description, but that as the basicness of it. creatine is like an energy supplement for muscles. as for what to take, regarding brand, that's really up to you. just make sure there isn't a shit ton of sugar in it. there should also be at least 20-30 grams of protein per serving. whey is the preferred type after workouts because it is more quickly absorbed. casein is good right before bed as it is more slowly released and will also help make you less hungry when you wake up.
whatever you do, remember that a supplement is that, a SUPPLEMENT. do not replace a well balanced diet with them. obviously there are exceptions, but your diet needs to be the most important aspect. i'll stop now. hope i helped