I learned to drieve because I did my back a bad injury, which I have now recovered from. Never did think I would but I did.
I drive pairs and singles. I did get a Stallion team together, but never did get to drive them competatively.
The pairs I drove were Father and Son, two stallions. You can see them at
www.geocities.com/tonkii2000/horses
All I can say is train your horse slowly. Driving has far more dangers than riding. Join the British Driving Society, read plenty, and don;t take risks.
BDS books are with reading, Sally Waldron writes well.