Simply open the Group Finder (default hotkey: I) and then select Dungeon Finder and Timewalking in the Type dropdown menu.

While Timewalking is active, you will gain a 50% bonus to reputations earned from quests and creature kills for all reputations associated with the corresponding expansion.

Rewards: One box containing a piece of gear from Normal difficulty Sanctum of Domination.

Quest Requirement: Complete 5 Timewalking dungeons.

You can also start the quest from within the Adventure Guide (Shift-J).

Caretaker Kah'toll in Oribos has a quest for you.

In addition, you can also complete Timeworn Keystone dungeons to earn powerful loot, as well as take on the challenges of the Mage Tower, available only while the event is active. Timewalking dungeons also have a chance to drop items that usually drop when you run them on Heroic difficulty, and you’ll earn reputation with a faction that is interested in the dungeon. Your character and items will be scaled down to a power level fitting for the challenge at hand, but bosses will yield loot appropriate for your regular level.

Players will be able to adventure into six of Legion’s dungeons to reap new rewards all week during this week’s Bonus Event. Prime your minds for a fel tangled chrono-spatial conundrum: Legion Timewalking is here!

Source of the corruption wow legion