Credits: ItsDarkwolf6
After you've tamed a capy, the only thing that is left is to put a saddle on it and you're ready to ride. To breed you need two adult specimens around and feed them with one of the following: Sugar Cane, Tallgrass, Seagrass, Sticks, Potatoes, or Sea Pickles.
There's an item called a Costume basket, its use is to equip your capybara with a monocle, a hat, or a cute scarf. Warning, can cause cuteness overload.