First I would put the horse in a smaller pasture by itself, when the horse has calmed down a bit I would have introduced a old or freindly horse. later i would put them in a bigger pasture.
Dont let the horse get a month rest or let it eat only hay, these horses need a lot of food!!
The thoroughbreds need their muscels but they dont have the muscels of a "normal" riding horse. So you need to work up the muscels alot!
With thoroughbreds everything happens alot faster than the qh for example. They reacting fast to unusual stuff might frighten the inexperienced. Remember these horses have been handeled by professionals only that know what they are doing. On the other side these horses are easy to handle.
Ride from start! Ride like its a green horse. You can lunge the horse but remember not to do it so often! its not good for the horses legs.
Sorry for my bad english XD, Im Swedish.