The Society of Mary is a group of people who believe in God and follow the Anglican religion. Think of it like a big club of people who all have the same beliefs and follow the same rules. They call themselves "Marists" which is short for the Society of Mary, and they work together to do good things in the world.
Just like how you have friends who share similar interests with you, the Marists have formed a community of people who believe in the same things and support each other. They have special ceremonies and prayers that they do together, and they also work on projects to help people who need it.
Being part of the Society of Mary is like being part of a team - everyone has an important role to play and they work together to achieve their goals. They try to follow the teachings of Jesus and do good things for others, and they believe that by doing so, they are fulfilling God's plan.