Ask about baptism: why should we baptize people in the name of the Father, Son and Holy Spirit? Why not just God, why all 3?
Read John 14:6-7…Jesus is God in Flesh. He is a significant part of God. We must go through Jesus to get to God. Believe in what He did for us and we will be saved.
Talk about the Trinity: Remember this: The 3 forms of God are similar to the 3 forms of water. Water (H20) has 3 forms (Solid, Liquid and Gas). Even though H20 can take 3 different forms, they all consist of the same molecule. God also has 3 different forms. There is the God of the universe (who created us and everything that exists), Jesus (God in Flesh), and the Holy Spirit (God with us). Even though they differ from each other, these are all forms of God. See the relation?