No beings or phenomena exist independently of other beings and phenomena. All beings and phenomena are caused to exist by other beings and phenomena. Further, the beings and phenomena thus caused to exist cause other beings and phenomena to exist. Things and beings perpetually arise and perpetually cease because other things and beings perpetually arise and perpetually cease. All this arising and being and ceasing go on in one vast field or nexus of beingness. And there we are.
In Buddhism, there is no teaching of a First Cause. How all this arising and ceasing began, or even if it had a beginning, is not explained. The Buddha emphasized understanding the nature of things as-they-are over speculation of what might have happened in the past or what might happen in the future. It might be said that the Buddhist version of Genesis is: Stuff happens, because other stuff happens.
Also, things are the way they are because they are conditioned by other things. You are conditioned by other people and phenomena. Other people and phenomena are conditioned by you.
The Buddha explained,
When this is, that is.
This arising, that arises.
When this is not, that is not.
This ceasing, that ceases.