Thank you for your question. Although such broad questions would require a series of discussions rather than an online answer, the question of knowing largely comes down to a number of presumptions about how things are known. Most people do not actually know what they have presumed or the nature of how presumptions are evaluated and that is how they can get into intellectual predicaments as our presumptions can simply arise from those that dominate the intellectual environment that we live in and digest through the arts.
For example, if we have presumed that all that can be reliably known must be known by the five senses, then with that presumption it is impossible to know that God exists. But why should someone take that presumption over the presumption that a human can know more than what their physical sense perception accounts for? If we presume that we can know through other than our physical sense, then we can know God through our other senses and trust those senses in the way that we can trust what we already know to be limited physical senses. So once the issue of presumptions is solved a person can rationally move towards establishing the existence of God and answering the other questions you have posed.
God is also known through a deep connection and feeling within the soul.
If you would like to discuss your questions further please feel free to reach out on social media via my Facebook account.
May you always be successful