Here’s a helpful thought about how we can know the Triune God without necessarily being able to explain the Trinity:
A child by the age of five has learned, we are told, an astonishing amount about the physical world to which he or she has become spontaneously and intuitively adapted – far more than the child could ever understand if he or she turned out to be the most brilliant physicists. Likewise, I believe, we learn far more about God as Father, Son and Holy Spirit, into whose Name we have been baptised, within the family and fellowship and living tradition of the Church than we can ever say: it becomes built into the structures of our souls and minds, and we know much more than we can ever tell. This is what happens evangelically and personally to us within the membership of the Church, the Body of Christ in the world, when through the transforming power of his Word and Spirit our minds become inwardly and intuitively adapted to know the living God. We become spiritually and intellectually implicated in patterns of divine order that are beyond our powers fully to articulate in explicit terms, but we are aware of being apprehended by divine Truth as it is in Jesus which steadily presses for increasing realisation in our understanding, articulation and confession of faith. That is how Christian history gains its initial impetus, and is then reinforced through constant reading and study of the Bible within the community of the faithful.
Fred Sanders, The Deep Things of God, how the Trinity Changes Everything, page 50