What do i need to mail in with my first payment since i set up a payment plan through turbo tax?

I have no idea how any of this works, i filed through turbo tax and set up direct debit for my monthly payments, i agreed to pay a certain portion for the first time payment and then a small monthly, i cannot find instructions on what i need to send in with my first payment outside of the voucher for that agreed first payment, does the irs already have and accept my payment plan that i submitted through turbo tax or do i need to send in my whole return through the mail even tho i filed here i would greatly appreciate some solid info on this because there is no answer anywhere