The Arsh and Kursi according to the view of the imams of Ahl al-Bayt, upon them be peace, is an expression used by Allah to denote His Dominion (mulk). It is not literal. Imam al-Hadi and his grandfather, Imam al-Qasim wrote about it in their Collections. If you want an explanation, let us know and we can explain it to you, with the permission of Allah.
[As was mentioned, the imams, upon them be peace, interpreted the Arsh and Kursi as metaphors for Allah’s Rule and Dominion. There are also narrations that say that the Kursi refers to Allah’s Knowledge. It says in the Kaashif al-Ameen (a commentary on ‘Iqdu ath-Thameen):
There is disagreement about the meaning of Arsh, and there are two opinions. The first opinion is that of Imam Zayd bin Ali, al-Qasim, al-Hadi, al-Murtada (i.e. the son of al-Hadi), the author of Al-Asaas (i.e. Imam al-Qasim bin Muhammad), Imam ash-Sharfi (the commentator on Al-Asaas), and others. That opinion is that it is an expression of Allah used to denote His Rule and Authority.
He went on to say that some scholars interpreted it to be literal. Regardless, none of the imams interpreted to Arsh or Kursi to be the resting place (sareer) of Allah!
You can refer to our book “The Establishment of Clear Exposition” You can also refer to our translations “The Precious Necklace” and questions #125 and #126 of “One Hundred Eighty Issues of al-Qaasim”]