This really depends on what approach you wish to take and what is your current profession or practice.
If you are not already qualified and/or practicing then you will need to find a trainer that will take you on and provide a full foundation in therapeutic practices. These organisations will have their own defined prerequisites for beginning study. Prerequisites vary from trainer to trainer.
If you are already a qualified and practicing then you can find a trainer that will provide you with a professional qualification that extends your current practice. At Athena Herd our Certificate and Diploma have been specifically designed to embellish and build on existing qualifications.