You can include details of your interactions. Roughly, it means that you were either the first one who informed someone about the fellowship or that your encouragement was the main reason they applied. A good rule of thumb is "if we would ask the fellow, would they say you are the reason they applied". Please list fellows by their first name  and last name, as if you referred a group, we do not know who belongs to which group, so precision is needed. The final decision about bounty eligibility is ours.