How to calculate the amount you owe to the IRS

Hello, this is my first year ever paying taxes. I am a SMLLC, and I already set up an account with the IRS to use Direct Pay. I did not pay estimated quarterly taxes this year because I knew I would not be paying more than 1000 dollars in taxes. I also made less money than the standard deduction. Do I wait until after I send in my 1040, SE, and Schedule C, to pay the IRS, or how exactly does that work? Once I send in the forms with Free Tax USA or Turbo Tax, will the IRS show the amount I need to pay online, or do I pay based on how much is owed on my 1040? If it's on my 1040, would that be line 23? Thank you