Theism acknowledges at least a God, a Creator. Acknowledgement of such is making use of the faculties of logic and reason, apart from divine revelation, to recognize a deity.
Once someone acknowledges a creator, they implicitly believe that they are a created person, not just of their parents, but of a higher power. Using an analogy of regular human life, a person who creates something - let’s use the example of parents who have children - has a reason for the creation and expectations for it. So just as parents create a child out of love and have expectations for him, God created humans in His image and has expectations for us.
Then the questions which follow are: can we actually know God? what is He like? what are His expectations for us? and, has He revealed these things to us?
We know He has, first and foremost through his Son Jesus Christ, and now through the Church.
So I think trying to take a personal approach like this (creation and expectation) is one way to make this leap without overcomplicating things or going off into multiple tangents.