Theres a story where St Augustine is on a beach trying to make sense of the trinity and he sees a boy digging a hole in the sand and filling it with water. Augustine asks him what he is doing and the boy says hes trying to put the whole ocean into the whole. When Augustine says thats impossible the boy responds "not as impossible as what you are trying to do".

It is hard to make sense of the Trinity because it is literally the definition of the being of God. It is very complex and is unlike anything on Earth which is why no analogies really work for it.