Got it. Yes, this is a new feature in TT - you can setup payment plans directly through us.
You do NOT have to make a payment on your own. If your plan isn't setup by the first due date, then you might need to make a payment, but if you don't the worst thing that would happen would be a very small amount of interest on that payment.
What I would recommend is a week or so before that first payment is due, follow the instructions in the second link I provided (in the above answer), and check if your payment is scheduled. If not, you can make it directly. Everything you do going forward related to your payment plan, will be through the IRS - not TurboTax.
