What does it mean that you need to insert Ginoring on the first day of your cycle?

Hi, I have a question about the time of insertion of the first puck. I had not used any hormonal contraception before. I got the period on the night from Wednesday to Thursday, while the first puck I put on on Thursday at 20.30 (due to a comfortable hour). So I fit in 24 hours after the start of the tailoring. I understand that then Ginoring works already 100% and the next day I could already have a relationship? Best regards