ANND...in case it wasn't clear.
The SS/Medicare taxes you expect to pay, those are just added into the quarterly estimates that you pay. You don't pay them separately. Then, when you file your yearly taxes, those the total of the quarterly estimates you've paid in will be used as a credit against the total of your SS/Medicare taxes due, plus any regular income taxes that you are assessed.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
