We don't have 'pastors,' and all our clergy, or 'bishops' are lay clergy, meaning they are unpaid volunteers who usually serve for about 5 years. They hold regular jobs and are just regular people. The Bishop leads the ward, but is not required to 'preach' a sermon every week. The members of the ward take turns speaking on various subjects that are suggested by the bishop. Perhaps there will be a theme each month and they may choose a subject from that theme. Today in our ward, three women each spoke on "choices" and how we make good choices and learn from our bad choices. It was a very good meeting.
Good summary, Gwenabob. I just want to add that we have lesson manuals for Sunday school and our other meetings (such as the women's Relief Society.) For example, this year we are studying the Old Testament in Sunday School. All across the world, members will be studying using the same manuals. Different people may emphasize different aspects of the lesson. When my husband travels and attends a different ward than I, we can still discuss what we learned.