How is the NFL Playoffs determined?

Ive been researching about it but still get confused. I see if the chargers win all there upcoming games and kansas city loses at least one chargers advance with a wild card or something like that and I see if steelers lose all there games then they are tied. How are tie breakers determined ? How are the wild card games determined? Do they advance to the super bowl? I would gladly appreciate it if you guys give me a link of a chart or if you guys explain it to me . THANKS.