Tax question regarding my teen

My son just got a new job at a pizza place and they just opened. My son was told during the interview that he would have to pay taxes at the end of the year. His boss has a very thick accent so he didn’t really understand what he was talking about and I assumed he was trying to tell him that money would come out of his check for taxes at the end of the year. Fast forward to his first check and it’s hand written, including the pay stub and no taxes taken out. Is this how it is suppose to be done? I’m a confused mama. What percent should he save per paycheck? I’m honestly not a fan of any of this. He is a kid and knows nothing about any of this.