How do you know God exists?

Here is a basic yet huge question in the Catholic faith. First of all, every Catholic must have faith that God exists, but if faith is not enough, St Thomas Aquinas has made 5 reasons for why he believes God exists. First, the argument for motion. Nothing can move by itself; there is always a first mover. This can also be made clearer by Newton's law: an object in motion remains in motion and an object in rest remains in rest unless acted on by an outside force. So in the beginning, everything was motionless until it was acted on by an outside force (God). Secondly, there is efficient causes. This tells us/points out to us that nothing exists prior to itself. I wouldnt exist without my parents, they wouldnt exist without theirs, and this continues up to the first people on earth. Then they could be argued to have developed on their own, but now where did the world come from? That could be argued to have come from the big bang, but if the big bang was true then what created the particles and bits of matter that were necessary for the big bang to take place? Everything came from something else. Thirdly is the Argument from Possibility and Necessity. "Since objects are countable, the objects in the universe are finite in number. If, for all existent objects, they do not exist at some time, then, given infinite time, there would be nothing in existence. (Nothing can come from nothing—there is no creation for individual existent objects." This pretty much explains that if everything in the world is finite, then there is a chance that nothing would exist at one time, and if nothing exists at one time then nothing can be created out of nothing. Fourth, Argument from Gradation of Being proves the existence of God. "There is a gradation to be found in things [where] some [things] are better or worse than others. Therefore there must also be something which is to all beings the cause of their being, goodness, and every other perfection; and this we call God." Since everything in life that we characterize is based on the perfect example of that characterization, then there must be something that perfectly characterizes love or happiness, which ultimately can only be God. Fifth is the argument of design, which says that "We see that natural bodies work toward some goal, and do not do so by chance.Most natural things lack knowledge.  But as an arrow reaches its target because it is directed by an archer, what lacks intelligence achieves goals by being directed by something intelligence.Therefore some intelligent being exists by whom all natural things are directed to their end; and this being we call God."