Trainers help horses and players perform better in shows.
Horses and Players have a bonus for each discipline, that can go from 0 to 100%. Each game month 10% is lost and needs replacing.
Trainers help improve that bonus so that the results in shows will be improved.
Trainers also can help improve the horses' specialization, by training them in a certain discipline.
Trainers do not have workshops, so they cannot manufacture tack. They have however arenas and other players can register at one trainer's arena and pay for the requested services.
Trainers can access their training arena by clicking the icon.