Buddhists are taught not place emphasis on this as the aim of
Buddhism is to develop wisdom and compassion and thereby attain
Nirvana. Knowing how the universe began can contribute nothing to
this task.But since you have asked we will discuss it briefly here.

All religions have myths and stories which attempt to answer this
question. In ancient times, when many simply did not know, such
myths were adequate, but in the 20th century, in the age of
physics, astronomy and geology, such myths have been superseded by
scientific fact. Science has explained the origin of the universe
without recourse to the god-idea. What does the Buddha say about
the origin of the universe? It is interesting that the Buddhas
explanation of the origin of the universe corresponds very closely
to the scientific view. In the
Aganna Sutta, the Buddha described the universe being destroyed and
then re-evolving into its present form over a period of countless
millions of years. The first life formed on the surface of
the water and again, over countless millions of years, evolved from
simple into complex organisms. All these processes are without
beginning or end, and are set in motion by natural causes.
Infinite Causes is so named because
of the belief that there are an infinite number of causes and
conditions that made the world the way it is. There is no first
cause or one cause because all things are intertwined in an
endless web of causality with no beginning and no end. Both
natural and supernatural forces may be involved.
There are many universes, of many possible types. We happen to be
in one. There may be both natural and supernatural causes that set
the physical conditions of our universe the way they are and
allowed life of our type to come into being. However, there is no
need to believe that this is the best possible universe
An infinite web of causes and
conditions affects the development of every instant in our lives
and the world we live in. This includes our own actions. Karmic
theory is based on the unseen bonds between living sentient beings,
whereby every action we take has consequences. These consequences
have an impact not only on all around us but also, through stress
on the interconnections between us and everything else, reflect
back on ourselves as well (either in this lifetime or in the
future). However, this is not fate, because you can change
your own karma, or by acts of compassion and mercy, alleviate the
negative karma of those you help. In a Buddhist worldview, we help
create our own reality. The discoveries of quantum physics do not
trouble Buddhists the way they do members of divine plan based
faiths, because the transitory nature of each moment was well
understood by the Buddha, as was the interconnected condition of
our existence.
Quantum physics theory reveals a
universe of constant change, where events are only probabilities
until there is an interaction with an observer. This effect of an
observing mind on the future of the universe is consistent with
Buddhist concepts that we are all interconnected and our actions
and even presence can affect everyone and everything around
us.
The Buddhist view of the world allows changes that occur over eons
measured in millions of years or even billions of years.
The Buddhist view of the world is that nothing that arises
is permanent; all things are temporary and transitory. Because
there is no design or plan, there is no objection to the
idea that the worlds ecosystems have changed so dramatically that
whole species have died out.
The evolution of life is, of course, the aspect of science that is
causing the most vicious debate in theological and philosophical
circles (since it deals with our direct ancestry, not obscure math
like quantum theory or the theory of relativity). However, the
fossil record clearly shows organisms existed that mix
characteristics of fish and amphibians, amphibians and reptiles,
reptiles and mammals, reptiles and birds, and so on, none of which
would exist in a Creationist universe.
The Buddhist view that many beings
in many universes would be capable of sentient thought and
potentially capable of being affected by karmic bonds means.There
is no objection to common ancestry with other species on Earth and
no belief that such ancestry lowers the value of human life at
all
The idea of the evolution of life has been tested with two
completely independent sources of information. One is the fossil
record. The other is the DNA sequence evidence that all life known
on Earth has common roots. Again, there would be no similarity
between molecules in a human body and an ape, let alone a mouse, if
these organisms had been built uniquely for their specific niches
and tasks in a divine plan. Instead, each is clearly a modification
of a common set of parts, stretched by expanding gene families and
altering gene regulation and development.