Gothika says:

The more massive a star, the quicker it burns off it’s fuel, and the qicker it dies. In the very early universe, hydrogen was exceedingly abundant. It all clumped together and formed the first stars. Now hydrogen ins’t very heavy, so a lot of it was needed to weigh the star down enough to begin fusion in its centre. So the first stars were very, very massive. Once they die, they leave a massive core behind. This core cannot sustain fusion, so it collapses so much that it becomes a black hole. Some supermassive black holes may have even merged, adding their mutual masses into one even more massive black hole.

professor Einstein says:

if your question is what was the very first thing that stars, black holes and all matter came from, i don’t know, no one knows for sure. that’s what we are looking for. there is a theory called “the theory of strings” which explains that everything in the universe is made of tiny strings. if this theory is proved to be true, then humanity will get the answer for most of the questions we have about the universe. it will even give us the ability of teleportation from one part of the universe to another and much more.