1)
To what must he put his heart?
1.
Vilna Gaon: To understand hidden matters. We do not expound Ma'ase Merkavah even to one Talmid, unlike he is wise and understands by himself (Chagigah 2:1).
2.
Malbim: To understand the Nimshal and secrets hidden in the vision. He was brought here to see the ultimate vision, and tell Yisrael in order to console them and strengthen soft hands.
2)
What does "l'Chol Asher Ani Mar'eh Osach" refer?
1.
Rashi: Binyan [of the Bayis].
3)
From where was he brought to here?
1.
Rashi: From Bavel.