Mary is a intercessor?

Think of it this way. God is the main character just like in a play. You have other actors too such as Mary and all of the other saints. They help deliver the message to God and communicate with the main character. Just like how on earth you tell friends and family to pray for you well you can tell saints in heaven to pray for you as well. It is more powerful too with the saints and Mary because they are in the kingdom so they are closer to God and can communicate with him like a next door neighbor. :-)