After obtaining a Greater Rift Keystone from the Realm of Trials ([ Ссылка ]), put it into the Nephalem Obelisk to enter the Greater Rift.
Important: before clicking "Accept", make sure you have the correct skill setting and gear, as once you open the Greater Rift, you will not be able to change them until you finish it!
The higher the Greater Rift level, the tougher the mobs. (This video is a level 23 Greater Rift, which I estimate is roughly equal to Torment 4/5.) Once you entered the Greater Rift, you have 15 minutes to clear it. Killing mobs fills up the purple bar on the right. Make sure you pick up the purple orbs dropped by elites as they help fill up the bar faster. When the purple bar reaches 100%, a Rift Guardian spawns. Kill it and the NPC Urshi appears. If you complete the greater rift within the 15 minutes time limit, she will let you choose to upgrade your Greater Rift Keystone or Legendary Gems. If you failed to complete it in time, she will only upgrade Legendary Gems for you. ([ Ссылка ])
Also note that most of the mobs do not drop any items. However, killing the Rift Guardian will give you plenty of loots, usually include some blood shard, one or more legendary gear, and more importantly, legendary gems!
