To complete this mission in Red Dead Redemption, return to Bonnie's house, enter it, and watch the cutscene. Bonnie will introduce you to her father — Drew MacFarlane, who supports your idea of dealing with the bandit Bill. Breaking in horses is Drew's favorite activity, and that's what you'll be doing. Mount your horse and follow the man to the wild herd of horses. Your task is to throw a lasso around the neck of one of the horses in the herd. We advise aiming in advance, as this will increase the chance of catching the horse with the lasso.
After successfully lassoing, dismount your horse and jump on the captured one to break it in. Balance to prevent being thrown off the wild horse. Once you manage to tame it, mount your horse again to continue the roundup. Return to the ranch, following Bonnie. Hand over the horses to the woman's father so he can put them in the pen. Head out for the next herd, rumored to be outside the town. Upon arriving at the marked location, follow the instructions and don't lose sight of the herd, or you will fail the quest.
Now lead the herd to the canyon marked by the yellow point on the mini-map. Upon arrival, Bonnie and her helpers will already be there, surrounding the hoofed animals. One of the stallions will start to run away. Your task is to keep an eye on it and catch up, throwing the lasso on it. Mount the horse and tame it, then head back to Bonnie. Upon completing the mission, you will receive +75 points in the Honor category.