God is a spirit and we must worship him in spirit and in truth. He created the universe and sustains it. He is the ultimate power of the universe and all the dimensions he inhabits. He also is a triune God which is God the Father, Jesus Christ the Son, and the Holy Spirit. These three are one contained in God.
The trinity has been described in different ways. I like to describe it like an atom. There are the neutrons which symbolize God the Father, the protons which symbolize Jesus Christ, and the electrons which symbolize the Holy Spirit. Remove any of these components and the atom either falls apart or implodes. All three types of particles must exist in order for an atom to exist other than hydrogen which only has one particle in the nucleus and an electron. All other atoms can be used as an example.
I believe that God may be an interdimensional person. He may "physically" exist in his all-powerful self in one dimension we often refer to as Heaven. But he can interact with all other dimensions. When we pray to God through Jesus Christ, we can come in contact with the most powerful source of energy in the universe and all its dimensions. The Holy Spirit may indwell the believers. And Jesus, when he was physically on earth, was the embodiment of God. But all three are God.
Another example I like to use is a radio or TV program. There is the program which to people outside the station is invisible if it is done in a studio. That could symbolize God the Father. The station and transmitter with its transmission tower would symbolize Jesus Christ which we can see. The program transmission would symbolize the Holy Spirit which is invisible. But it can be received by anyone who is tuned to the station. Since all believers have the Holy Spirit dwelling in them, it's as if we are tuned to the program known as God which we have received. If one is not tuned to the station, in this case Jesus Christ, he can not receive the program, known as God the Father, which was carried by the transmission, known in this case as the Holy Spirit. The trumpet of God and his voice will only be heard by those that are born-again just like only those tuned to a station transmitting a civil defense signal will hear the signal.
God isn't an old man with a beard and white hair. Since he can't be seen, being a spirit, we will only know what he looks like by looking at Jesus. As Jesus told his followers, if you have seen me you have seen the Father. Not all people are children of God either. Jesus told the Pharisees that they were of their father the devil. Many even doubt he exists or if he did, he is dead. If that were the case, the universe would fall apart. God has the ability to suspend the laws of science and do miracles.
When angels are dispatched to serve humans, God allows them to shift from the Heavenly dimension to this one to perform something special. Lives have been spared by angels. People have been punished by angels. Angels are normally all around us in their dimension. But when they shift to this one, they become physical beings.
God, on the other hand, appears to people in the form of Jesus. He can "speak" to people and convince them to do things that go against human logic. Abraham traveled from Ur which was in one of the most fertile areas in the world to the land of Caanan which is now Israel. He had no idea what to expect. But God told him to go and he went. Today, Israel is much more fertile than the land in the region where Ur once existed. Only Godly logic, which to most people seems like foolishness, can explain why Abraham did what he did.
Other decisions made by people who were led by God didn't make sense logically. But as the Bible says, God's wisdom is foolishness to man while man's wisdom is foolishness to God. God withholds his judgment when we would inflict it upon those we feel need to be punished. He is patient and allows people until the last possible moment to turn to him and trust in him. If we ask anything of him, as long as it is in his will, he will honor our request. Sometimes the answer is other than what we expect. But as the Bible says, all things work together for good to them who love him and are the called according to his purpose.
God created and sustains the universe and all its dimensions and is still a personal God who will help his people when they need it. Those who are believers will in time shift to the Heavanly dimension to live with him forever. We don't need to understand God. But we do need to trust in him and let him control our lives. We may not fully define God. But as long as we believe and trust in him, he doesn't need to be defined.