Horses are amazing in multiple ways but these large gentle giants need lots of attention and supplies to take care of them. These are the main supplies to begin taking care of your gentle giant. Of course you're going to need hay for food and water. Along with that you're going to need a harness and lead. If you don’t exercise the horse then it may be agitated easier and cause more problems. Plus you can’t tie them up to brush them or put a saddle on them without a lead. 

Then shelter and bedding so it’s easier to clean the shelter. The cleaner the shelter the happier the horse, the easier the cleaning the happier the owner. You're going to want a brush to get all the dirt and sweat out of the horse's coat. Not only does it help clean the horse but it can calm you and make your horses bond with you stronger. It’s better if you have a strong bond with your horse because it will help the horse trust you. 

From personal experience, I know taking care of horses is difficult and tiring. At the same time though, it’s calming and peaceful. After taking care of the horses I’d go for a ride then brush them. It always helps clear my head and gives me time to think. I highly recommend owning a horse or working at a horse stable.