The root of all fluent mappings is the ClassMap<T> class, which represents a mapping for a single entity. As explained in GettingStarted: First Project, all your mappings derive from ClassMap<T> where T is your entity type; all mappings for an entity are done inside the constructor of your derived class.
public class PersonMap : ClassMap<Person>
{
public PersonMap()
{
Id(x => x.Id);
Map(x => x.Name);
}
}
ClassMap<T> defines many methods that you can utilise in the constructor to create your mapping. You can view different examples from the menu on the right.