How is a mission set up/organized?

When talking about my mission, I very often say 'we', because on a mission, you are always with a companion--we go two-by-two. Jesus also sent his apostles out two-by-two, like it talks about in Mark 6. A female missionary, called a 'Sister', is always with another Sister, a male missionary, called an 'Elder', is always with another Elder. Over the course of my mission I served with 5 different sisters.

A Mission President is the man in charge of the missionaries in the mission. He, while consulting with the Lord for revelation, decides where we serve, with whom and how long.

We are in companionships that are then grouped into districts, which are in turn grouped into zones. Missionaries are also assigned to serve as District Leader or Zone Leader or Assistant to the President. They then help, train, and organize the missionaries under their jurisdiction.

Every 6 weeks there is the possibility of getting 'transferred' or reassigned to another area (with another companion and another church congregation). Another possibility is that another sister will get transferred to your area to serve with you. The third possibility is that the companionship (the pair of missionaries) stays the same for the next 6 weeks. The fourth possibility is that both are switched out and two new ones come in (that's called 'whitewashing an area'--I did that once). And the fifth possibility is a variation on the fourth--two missionaries 'open' a new area that previously did not have missionaries assigned to it. Over the course of my mission I served in 4 congregations.

Some missionaries changed much more often (and also traveled further afield for the changes :) ), but as the Lord would have it, I stayed in and around Frankfurt for the whole time, even though our mission area covered almost half of Germany!