Simply create an in game avatar, and select what kind of starter horse you want, and away you go into the Island World of Jorvik. It's a place steeped in lore, mystery and lots of horseback riding. You begin at Moorland Stables, where you're instantly introduced to the game and swept up in a grand adventure. Now, I won't spoil anything for you, but there many things to do on the island. It's a pretty massive island too, so you can bide your time exploring if you'd like. In fact, that's encouraged. Not all of it will be open to you right away, but you'll unlock more and more of it as you explore and go through the story.
The best part about the game is that along the way, you can buy more horses! There are many different breeds to choose from. I have 5 horses right now. A snow white Tinker Horse named Diamond Dust, a cute little Jorvik Pony named Violetdawn, a gorgeous pale pearlescent gold Morgan named Everdawn, and my personal favorite, a pale Haflinger named Honeydew (as seen in the picture above).
The game is incredibly detailed in that you have to take care of your horse properly in order to keep it happy and be able to get good times in races. You have 4 ways of taking care of your horse; feeding, watering, hoof picking, and brushing. Do all these at least once a day and your horse is happy and healthy and ready to ride. Don't, and your horse is going to be unhappy and sluggish and not easy to handle.
You can also do basic chores around each town's stables to earn extra in game currency, including feeding and watering the horses, and mucking out the stables. Yup, in this game you can actually scoop up digital poop with a digital shovel!
Anyways, here's my character in the Star Rider stables. That's the stables you get when you become a Star Rider, or member in the game. You can become one by buying a membership with real world currency. You can also get Star Coins, the coins you use to buy new horses, with real world currency.