In World of Warcraft Classic, you can first accept the Zul'Farrak quest in Gadgetzan. The number of tasks is 5, and there are many non-elite monsters in the dungeon, so it is relatively easy to complete.
There are many trolls in the dungeon, and 20 of the items they drop can be picked up. This is one of the key steps in Zul'Farrak's mission.
After completing the troll monster pickup, enter the 100-regiment boss battle in the dungeon. After defeating the boss, talk to the sergeant, then kill him and pick up the quest items.
After completing the mission after the Hundred Regiment Battle Boss, go to the Shining Plains to take on a new mission. After completing the mission, you will receive an accessory that speeds up your mount.
In the Hinterlands, you can take on an interactive quest. This mission requires you to use a poison sac. After killing monsters in the Hinterlands, go to the Golden Village of Durotarson for advice. After a series of tasks, you will receive a new task.
Within the instance, there is a stone slab in the center of the room where the scarabs are concentrated. By reading the tablets, you can learn about the Spider God and complete quests.
The above is how to complete the Zul'Farrak quest in World of Warcraft Classic. Hope this helps!