What does (after-tax additional contributions) mean? I did open a Roth IRA this year. But idk if that’s what it means

Yes, the contribution to a Roth IRA would be after-tax contributions. Therefore, you can withdraw contributions you made to your Roth IRA anytime, tax- and penalty-free. 

I suspect that this is a question that is appearing the Retirement Savings Contributions Credit section of TurboTax.  If so, this question is asking if you made any after-tax contributions to an employer plan like a 401(k), not anything about contributions to a Roth IRA.