I set up a payment plan with the IRS. But I don't know where to send it? What form of payment to use? when can I start sending these payments? "

I completed my 2017 taxes. I owe 843. I set up a paymet plan with the IRS. I have been instructed by Turbo Tax to Mail in my first payment to IRS along with payment voucher 1040-v. But I dont know where?, What form of payment to use? And when can I start sending these payments?