Anyway, however you choose to get to the addon's menu, choose guide list and then pick the zone you want to quest in. There are some zones that will autoselect based on quests in your log, but not all guides or all quests are set up that way. (If you don't want to switch to a guide that auto-pops up choose "not now" or "never") As you can see in the screenshot, there are various categories of guides. Most max level content (such as Argus) is found in Achievements rather than leveling.
One thing to realize is that once you hit 15 you have a lot more options for speedy leveling. Right now (you seem to be level 9 at the time of this writing) you only have questing and grinding, which are inefficient. Once you get the ability to use the Random Dungeon Finder (often called LFD, Looking for Dungeon) you can queue for dungeons in between questing. Often one dungeon, up until 25 or so, will give you most of a whole level off the XP and quests within.
The Broken Isles are unique among WoW continents in that you can progress through zones in any order you want. Once you have made it through the initial quests in Legion, you are free to move about four of the new zones — Val’sharah, Azsuna, Stormheim, and Highmountain — as you wish, with enemies, quests, and rewards scaling to your level. The fifth zone, Suramar, is mostly locked away until you’ve reached a certain point in the story.
It comes with a detection system for quest which monitors your previous actions and makes improvements based on them. A directional arrow that appears on the screen will indicate the best direction. It is fully automated hence saves you the trouble of having to click when moving to the next level. By following the guide you will require fewer than 7 game days to move from 1 to 80. You can begin from mid-level and let the guide lead you through the next levels.
Just before Battle for Azeroth goes live, you will want to log all of your characters out in the zone of Silithus so that you can acquire the quest to talk to Magni and obtain your Heart of Azeroth (refer to our Heart of Azeroth guide for more information about this item). This is the new artifact-type of piece of equipment that you will use for all of the Battle for Azeroth expansion. Once you acquire your permanent neck slot piece of equipment, get back to Stormwind or Orgrimmar to begin your scenario that leads into the introductory areas of Kul Tiras and Zandalar.