Let’s start with the basics. At its core, World of Warcraft is a saga that centers on two warring factions: the aforementioned Horde and Alliance. They’ve been fighting each other since the days of MS-DOS, locked a never-ending war—save for those rare moments where they attempt to team up to counter a greater threat—that has taken them across continents, into space, and through time.
These guides are completely automated and work in-game, so you can see step-by-step instructions as you play. The guides automatically move to a new step as you complete the quests. You are told where to go i.e. the questgivers for accepting and turning in quests along with where and how to complete the quests. Zygor has more steps and details, which would be more suited to beginners. Dugi condenses the info into fewer steps, but still has all the necessary questing info.
Incursions are a new world content activity that are unlocked when one character has unlocked World Quests. This feature is unlocked account-wide meaning that all characters on that account can access Incursions even without being Level 120. This provides for a lucrative experience acquisition method that is available in a similar pattern to what Legion Invasions offered with nearly an entire level earned by completing an Incursion series which involves four World Quests and one mini-scenario at the end. These also grant item level 370 weapons and Azerite armor, so they should be done any time they are up. Incursions follow a similar schedule to Invasions and are available for 20 hours once they are initiated.
Special mention is the Darkmoon Faire Top Hat and WHEE! buff. While not always available due to the DMF being inaccessible most of the month, if you happen to be leveling when the DMF is running, it might be worth your time to go and get these. AFAIK they do stack with heirlooms, although I have not personally tested it. Fair warning: These buffs do NOT stack with each other, and the hats disappear after the DMF goes away later in the month(unless you only log in when the faire is running).
Kul Tiran human (8.1.5) - "Kul Tiras was founded by fearless explorers who sailed uncharted waters in search of adventure. As a key member of the Alliance of Lordaeron, the Kul Tiran navy dominated the seas of Azeroth with its legendary fleet. But after years of turmoil and hardship, the kingdom grew isolated and vulnerable to dark influences. Thanks to the help of brave heroes, House Proudmoore has been restored and Kul Tiras is poised to fight alongside the valiant Alliance once more."
Blizzard also has a great New Player’s Guide, split into four major sections, as well as its “A Return to World of Warcraft” compendium. And be sure to check out Blizzard’s online forums, especially the New Player Help and Guides forum, where you’ll be able to find more information, ask questions, and engage with some of the World of Warcraft community’s most helpful members.
This leaves players chasing an endless loop of trying to get higher level Azerite gear — which can only reliably be gained through raids and isn’t available in Mythic+ — but only the pieces with exactly the right traits will actually be an upgrade. It’s even possible that some items that should be huge upgrades are nullified by the loss of a specific trait that makes one ability do more damage than the others.
You can try joining a Discord server themed around the class you’re playing, how you like to play World of Warcraft (achievement hunting, dungeon-running, player-versus-player combat, etc.), or your location, to name a few examples. World of Warcraft also has player communities built directly into the game. Find a community themed for newbies, or whatever else you want, and you’ll have a great resource to go to with questions. You might even make a few friends (or fellow adventurers).