Attestation of School transfer certificate when moving from other GCC

Dears,
Can any one of the blog members brief what are the required attestation(like Ministry of Education/ Indian Embassy endorsement etc.) on School leaving certificate/ Progress report when moving from a GCC country to Muscat, Oman. My children are presently studying in Indian International School and follow the CBSE curriculum and we will be moving shortly to Oman in few weeks.

Thanks in advance.