Start by asking who likes chocolate? Who loves chocolate? Who is an absolute expert and knows everything there is to know about chocolate?
Then pull out your bag of M&M's... Start asking...(can list on board) How many colors of M&Ms are there? How many are in a bag this size? How many of each color (can specify here?)are in a bag this size? Which color has the most? The least? How can we know if we're right? Aren't we just guessing?
Then point out that there is only one way to answer these questions truthfully - and that is to open the bag and see.
Give specifics of your bag. Colors, how many total - each color - most & least...
Now relate the bag of M&M's to the scriptures. Each story is like a single M&M. We've heard the story of Ammon, Alma, etc. These stories together make up our scriptures (the bag) But we don't truly know the scriptures and the truths contained until we OPEN them up and feast upon the words. We can become experts on our scriptures if we do as Alma challenged and experiment upon the word. And believe me --- it's sweet!