The first BHs as a result of the collapse of the first stars (Pop III stars) may play a pivotal role in shaping the early universe. In particular, Pop III X-ray binaries and supermassive black holes (SMBHs) as two products of the first BHs are important X-ray sources which may drive the thermal history of the IGM in the early universe. However, we are still far from the complete picture of these. A first step for understanding them better may be understand their formations. For Pop III X-ray binaries, I will talk about their formation rates estimated in a recent study and will argue that Pop III X-ray binaries could be more efficient at heating at Cosmic Dawn. Then when it comes to SMBHs, I will more focus on their formation mechanism itself and suggest one possible avenue to explain the origin of SMBHs at the center of galaxy.