First find a texture pack download it put it on your desktop right click it compress the folder and then once you have done that you want to go into your minecraft folder so go to finder click your username/library/application support/ minecraft and then you went to go to your texture pack folder after that you want to put your zipped folder of your texture pack into your texture pack folder go into minecraft go into mods and downloads then click it then exit out of it and reload minecraft then you got a texture pack on have fun!