You won't have your Diablo 4 mount right from the start of the game. Instead, you'll need to work your way through the campaign and complete Act 3 of the story to access it. Any additional mounts you've acquired, either through Twitch drops or as a preorder bonus, won't be available to use until you've completed the quest to unlock mounts either. Thankfully, this only applies on D4 Gold your first time through, as mounts will automatically unlock at level one with subsequent characters.

The world of Sanctuary is large, but at least you won't be tempted to dash past enemies that can give you valuable XP. You'll have to spend the first 30 levels running around on foot, but the good news is that you can fast travel around the world using waypoints when running just gets too strenuous. That said, if you want to learn exactly how to get your mount in Diablo 4, here's how to unlock it. 

How to get your Diablo 4 mount 

After you've finished Act 3 of the campaign, you're sent to Kyovashad to speak with Donan in the Cathedral of Light. If you stick with the campaign and don't do any side quests, you will likely reach this point at around level 30. Once you speak with Donan, you'll receive the Mount: Donan's Favor quest.

It's fairly straightforward from this point: head to Cheap Diablo 4 Gold  the southwest of Kyovashad's waypoint to find Oskar the Stable Master and speak to him. You'll get your first mount for free, though you can buy two others from the vendor section of any stable master's menu for 20,000 gold each. You can also customise your mount with trophies and barding here.