Marketing partnership to sell a book on equestrian learning via horse-related Instagram or Pinterest channels

I'm looking for someone who has an Instagram or Pinterest channel (preferably both) with a fairly large audience, and whose account content is niche or related to horses and equestrianism. The goal is to partner to market and sell a new eBook about equestrian learning. I will need your support in promoting the book across your platforms in a professional manner that is appropriate for your audience