According to evolution humans evolved from lower species and in turn those species also have evolved, so what was the beginning and how can all of this happen without conscious intent?

It is survival, not conscious intent, that drives evolution. 

Your question essentially asked for the beginning and, as it happens, I did some original research on just this subject. A year or two back one of our Asklings wanted to know who built the first dam and, after spending weeks at the public library, I was able to come up with the answer. Oddly enough, it also answers your question about the origin of life.

Long, long ago, in an ocean far, far away, there lived a boy amoeba named Adam and a girl amoeba named Eve. The tide swept them together and they coupled and in time they had two munchkin amoebas. They called the first one Cain, because they could, and the second one Abel, because they were able.

In time the family found their way out of the ocean and into a stream. Adam built a wall across it to hold back the fresh water.

Eve Amoeba said, "What's that?" but Adam didn't know and could only
repeat his name. He thought that if he did that three times it was as good as registering the patent. So he said, "Adam, A-dam, a dam." And that's how the world's first dam was built and why it's called a dam.

So now you know why people were put on Earth. It was to build dams, and you've learned that life originated in the sea.