Complex sentence: The Kingdom of Ndongo (or "Kingdom of Ngola") is the name of a pre-colonial African state in modern day Angola built by the Mbundu, a Bantu-speaking people inhabiting northern Angola.
Split into simpler sentences: The Kingdom of Ndongo (or "Kingdom of Ngola") is the name of an early-modern African state located in what is now day Angola. Ndongo was built by the Mbundu people, a Bantu-speaking people inhabiting northern Angola.