The second law of thermodynamics basically states that entropy is always increasing. Another way to think of it is that entropy, the measure of the state of the "disorder" of things, is at best, in a perfect process, a constant. But there are no perfect processes and so every process has at least some slight increase in entropy (overall).
You can look at a small process in some secluded system and in that process, you can decrease entropy (aka become more orderly) HOWEVER, to do so, somewhere else entropy (disorder) will need to increase AT LEAST that same amount (if the process was perfect). Example: You can put water in an ice tray and freeze it. Looking only at the water turning to ice, the entropy decreased (the water molecules turned from disorderly to orderly). However, to do so, you had to run your freezer (which takes more energy to run than it does to freeze the ice) so overall the entropy increased.