I did my taxes on turbo tax this year (usually I get them done by an accountant). I need to now do my sons. How do I do that without creating a separate turbo tax account

Please read this TurboTax Help topic on how to start a new tax return for another person.

If you are using TurboTax Online, you cannot prepare and file a tax return for another person using an existing TurboTax account. You'll need to create a new account for each of your sons, distinct from the account you used to file your return.

If you are using TurboTax Desktop, you can start a new return for each of your sons by clicking on Start a new return on the Welcome page of TurboTax.