Can someone explain the whole Jesus concept?

You are a sinner. Your sin has put you in conflict with God, even His enemy. "The soul that sins shall die." God has provided the Way for you to be forgiven in Jesus, when He died for your sins. If you believe in Him... you receive the forgiveness God has offered you. Jesus' sacrifice and His death will be accepted, in your place. All debt will be forgiven. He is the "Lamb of God".