WoW: Shadowlands - What are Timewalker campaigns, how to use Chromie Time

Timewalker (Chromie Time) campaigns can be accessed after reaching level 50 on at least one character.

The new Timewalker campaigns (formerly known as "Chromie Time") in World of Warcraft: Shadowlands are unlocked once at least one of your toons reaches level 50. Until then, only the expansion that will be synced at levels 10 to 50 will be Battle for Azeroth. The old expansions will still be accessible, but they will have more traditional level ranges that don't sync.

Timewalker campaigns in Shadowlands allow you to choose any previous expansion you desire and force level sync for levels 10 to 50. You will receive the starting quest for this expansion and can easily level up in this expansion. Timewalker campaigns can be redeemed at any time, and you can even suspend experience gains if you want to complete an entire expansion storyline without a level 50 interruption (you are teleported to your capital to start Shadowlands once you have 50).

To access the Timewalker campaigns, all you need to do is visit Chromie at the embassy in your capital city (Orgrimmar for the Horde and Stormwind for the Alliance). It will appear as an hourglass on the map and on the minimap. Talk to him to choose your "campaign", and off you go. Note that you don't have to use Timewalker campaigns to level up others.

You can always go back to the Battle for Azeroth expansion (it will still sync at levels 10-50 until the next expansion replaces it with Shadowlands as a 'leveling' expansion), or tackle the previous expansions as you would before the level squish, but with new level ranges to compensate for the change. You can also turn off "Chromie Time" whenever you want, if you want. Finally, if you need to clear the initial tutorial triggered to reach your capital around level 10 to fully unlock Chromie time.