I wanted to emphasizes that God speaks through prophets, but that we are responsible to know what the prophet says and that we can ask God directly to know if it is right and the Holy Ghost will tell us.
1-Invite a child to come to the front of the room. Tell the other children to follow his or her instructions. Whisper simple instructions to the child, such as “Tell them to clap three times” or “Tell them to stand and march in place.” Do this once or a few times with different children depending on time and attention spans.
2- Explain that in the scriptures God has told us how each and every one of us can know when something is true. (James 1:5) That Joseph Smith followed this scripture and prayed and his prayers were answered.
3- Have another child come up (can be repeated) and do the same thing that was done in step 1. But this time ask the children how they can know if what the person acting out was really what I said for him/her to do?
Answer Ask me. Just like when we hear something we can ask God if it is true.
Question: How do we talk to Heavenly Father to know if something is true?
And then when we ask we will know in our hearts that we can make good choices and that we used the scriptures to know that we should ask God in prayer. We can feel the Holy Ghost when we learn something or hear something that can help us be more like Jesus. That we are blessed to have a prophets on the earth, and that we need to listen to what he says. But that we also need to ask if something is true.