Well the main goal is to defeat Ganon and it is told before you leave the plateau. Then you are also told to go first to Kakariko Village (if you use the minimap, set it so that it doesn't move, it's really less confusing). Once there you will be given the other important (but optional) goals.
Otherwise as seen with the plateau, it is to do the shrines and activate the towers. And every thing between is up to you. Mostly exploration, discovery and experimentation.
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This said, I am now fed up with this game, I have completed 67 shrines and found 201 seeds (180+ hours, I wasted too much time foraging). Next time I play it, I will focus on finishing the game. Then go back to Fire Emblem or try Genshin Impact.