I am a returning player and am looking for any guide or help on playing through each expansion with a guide of which quests need to be played and not all of the extra quests that are in game. I get a quest line started and then suddenly I seem to have 10 or so quest lines started and get lost in what I want to see is the main story Blizzard expected people to follow. Anyone know of a place or a guide with such a thing? I am not looking for power level which seems to happen when I get going down so many paths. For an explanation, lets say the Pandarin expansions (Mists of Pandaria). If I start it I have a single quest line and about 3 quests in I suddenly have what seems to be three quest lines. I would like to have one to play through and know I am on the right one, any help would be very much appreciated. Phillip
The challenge there is that some of those were gated behind sub-patches, but now you can just get them as you come across them. Usually, you can stick with the main one you started with, then go to the others (they often have titles/sections to help clarify and you can go from the top down in your quest log - as in main launch story is the top section, then the one below it is the next one, and so on). You can also look on wowhead for the list of quests associated with the quest you’re wanting to follow.
One of the best ways to do this would probably be to go play the WoW Classic Anniversary game. They just started TBC but you can roll a new character, play though the Vanilla zones and catch up.
Then as each new expansion comes out, play along.
You could do something similar with the regular classic but they are currently late Panda.
Another way would be to play Retail and use Chromie Time. If it is a new account you will have to play Exiles Reach to get to level 10 then level through Dragon Flight but once you hit max you can create new characters and play Chromie time for each expansion in order.
What I’ve been doing for older xpacs, especially for Dragonflight - I bought the xpac half-way thru that one, quests everywhere 
- is use Wowpedia. I believe they have good guides for all the xpacs although I haven’t checked all of them.
Example page:
https://wowpedia.fandom.com/wiki/Waking_Shores_storyline
It lists all the campaign quests in chronological order, and then all the side quests separately.
Thanks. I have been trying to work top down and maybe that is the only way but they still keep adding more quests at the top and thye are not campaign or do not seem to be a partr of the main story line, just side quests, Thanks .