As of patch 7.1 in FFXIV, whenever an MSQ is in your vicinity, the quest marker itself will show up on your minimap. Alternatively, you can always click on the quest itself in the top left corner ...
There are a couple of requirements you should know about before you can begin the new set of Main Scenario Quests in Patch 7.1. First and foremost, you need a level 100 Disciple of War or Magic ...