When God came into existence there was nothing else all was void. His first thought must have been self awareness. The only possible outcome of an omnipotent being becoming self aware would be for that awareness to be a mirrored reflection or that omnipotent perfection.
God the Father has Always existed
God the Son has always existed.
God the Holy Spirit has always existed.
None of them are created.
The Father is not the Son nor is He the Holy Spirit. The Son is not the Father nor is He the Holy Spirit. The Holy Spirit is not the Father nor is He the Son.
They are three separate but Equal persons. They are three persons with one nature. This nature is fully Divine. This means that all three are omnipotent (all powerful) and omniscient (all knowing).
All three of them are infinite and eternal, not in the mathematical sense, but in the philosophical sense. They exist out side of both time and space. This is why we can say that they have no beginning or end. But that is only true from our finite transitory minds.
The Son proceeded from the Father and the Holy Spirit proceeded from both the Father and the Son. Once again just to be certain all of you understand: None of them are created.