Installment sale taxes

[Horacio Gutierrez]

recognizes an installment sale as a way to defer a capital gain on a property sale. This can save on taxes by avoiding a bump up into a higher tax bracket if the seller had a huge gain." How do you pay less taxes by doing an installment sale, I thought your capital gains had it's own tax bracket amd ordinary had it's own tax bracket. How does capital gains lower you ordinary tax bracket, also in seller finance is the interest tax a ordinary tax or still capital gains tax?

Thanks,