LDS Leadership
General Authority Seventies preach the gospel and serve as special witnesses of Christ to the world. They assist the Quorum of the Twelve Apostles in preaching the gospel of Jesus Christ throughout the world.
In terms of hierarchy, after the General Authority Seventy there are other roles in the church who have input on primary teaching, relief society, young men/young women institute, and Sunday school. There are also local level leadership which are run at either a stake presidency level (collection of wards/congregations) and a ward level (where a bishop runs his own congregation). These can be viewed here.