Do I need to enter every payment from private lessons as separate rows or can I enter the total money I made from Private Lessons as one single row?

Are you filling self employment?   You can just enter the total income as Cash or General income.

How to enter income from Self Employment

https://ttlc.intuit.com/community/self-employed/help/how-do-i-report-income-from-self-employment/00/26653

Thank you very much!