1)
What is "Rosh Agol"?
1.
Rashi: In back of his torso [when he sits on it] was round. Malbim - it was his size, to support his back.
2)
What were the "Yados"?
1.
Rashi: They were gold sticks on which to rest his arms.
3)
From what were the lions made?
1.
Rashi: They were of gold. The Agadah (Targum Sheni) of Megilas Esther explains the form of the throne.