You will have to talk with flight masters in most towns or cities you visit in order to gain access to that settlement's flight path. Flight masters who have a stop you have not yet unlocked will have a green displayed above their head (and on the mini map), much like a NPC with a quest. Unlocking flight paths as you progress through various zones will allow you to pay for a quick ride to a destination you have previously visited. This method of travel is significantly faster than walking or riding a mount.
A demo of the game was available at BlizzCon 2018, and was downloadable on home computers for anyone who purchased a BlizzCon ticket or virtual ticket. The servers became available when Opening Ceremony started at BlizzCon 2018 and was set to end on November 8, but was extended until November 12. Players started at level 15, and the only available zones were Westfall and the Barrens. It was based on patch 1.13.0, essentially patch 1.12.0 ported to a modern infrastructure. The first day of the demo, there was a playtime limit of a cumulative 60 minutes with a cooldown of 90 minutes, applied through the BlizzCon Exhaustion debuff. The debuff was removed on the second day of BlizzCon 2018.