The people who meet here want to learn from the Bible: you can't see God, but Christians believe that Jesus was God's way of showing us what he is like, and we learn about Jesus from the Bible. The person teaching stands up to be seen - remember - everyone was standing so the teacher had to be above them so as to be seen!
The figures around the pulpit are St Peter (holding the keys), Jesus and St Paul (with the sword). This is because the full name of the church is "St Peter & St Paul, Dagenham".