Complex sentence: To replace Atahualpa, Pizarro installed his brother Túpac Huallpa as a puppet ruler but he died shortly afterwards so another brother, Manco Inca, was crowned in his place.
Split into simpler sentences: To replace Atahualpa, Pizarro installed his brother Túpac Huallpa as a puppet ruler, but he died shortly afterwords. Another brother, Manco Inca, was crowned in his place.