I found it. I’ll share.
Once you have completed the prologue and have started a new Bounty, Sarge’s Tale is added to your Mount Journal in World of Warcraft as an unopened present. Select the present and click Unwrap to add the mount to your collection.
Note: There may be a delay before you receive your mount. In some cases, it may take several hours to arrive.
If you still don’t see your mount, try the following steps:
- Log out of the Battle.net desktop app and all game clients.
- Start the Battle.net desktop app and log in to Hearthstone.
- Log out of Hearthstone, then into World of Warcraft. Check your mail for the mount.