You could also say than nobody knows how the universe was created if Brahma did not create it.
You could also say than nobody knows how the universe was created if Ymir the hermaphrodite giant god did not create it.
There are dozens of alleged creators of the Universe.
A better question is WHY? Why create such a huge universe for a relatively small population of evolved apes on one rather tiny planet? According to Douglas Adams, the mice contracted to build the Earth. A man named Slartibartfast did the fjords.
Earth was a giant supercomputer designed to find the
Ultimate Question of Life, the Universe and Everything. Designed by
Deep Thought and built by the
Magratheans, it was commonly mistaken for a planet, especially by the
ape descendants who lived on it. It was situated far out in the uncharted backwaters of the unfashionable end of the
Western Spiral Arm of the Galaxy.
Unfortunately, the Earth was destroyed by the
Vogons five minutes before the program was to be completed. The Vogons were sent by the psychiatrist
Gag Halfrunt, who thought his profession would cease if the Question were known. Later on, the Earth reappeared but all forms of the Earth were later demolished.