“Bless me, Father, for I have sinned. It has been about (x years) since my last confession. I have been angry x times, I have missed Mass x times, I have lied x times . . .(etc),. . .for these and all my past sins, I am very sorry”.
When the priest says, “. . .I absolve you in the name of the Father, Son, and Holy Spirit” he will ask you to make a good act of contrition.
“O My God, I am heartily sorry for having offended Thee. And I detest all my sins because I dread the loss of heaven and the pains of hell, but most of all, because they offend Thee, My God, Who art all good and deserving of all my love. I firmly resolve, with the help of thy grace. to sin no more, and to avoid the near occasions of sin.”
Do whatever penance Father gives you, and REJOICE! I am so glad for you!