Right click DG Guide Icon Button.
Go to: Home -> Leveling (expand by clicking +) -> pick a zone with a good mix of green/yellow quest (they give the same XP). Do not worry too much about the lvl requirement. If you’re 22 and there’s a 21-22 guide filled with green/yellow quests, then pick that. If you see a grey quest with a (*) this means it’s part of a chain. You may want to do it if you want the follow up quest. Up to you.
If there’s a quest not in your log, then go to Current Guide and double tick until there’s a red X. It’ll then skip all steps related to that quest. Same if you want to skip a grey quest. Just remember, you can’t red X in the quest tracker, has to be done in the Current Guide window.
Doing dungeons requires you to be more aware of your quest log, so it doesn’t fill up with grey quests. Some you have to delete and some quests you need to red X because you’re ahead of the guide.