Saying yes to Jesus is a commitment to follow Him and make Him the Lord and Savior of your life by trusting in what He did for you and not anything you have done or can do.
For it is by grace you have been saved, through faith and this is not from yourselves, it is the gift of God.
To say yes to Jesus, simply confess and believe.
If you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved.
You can use your own words, or pray the following:
"Dear Jesus, I confess that I am a lost sinner that needs your salvation. Forgive me of my sin, come into my life, and be the Lord of my life. Help me to move on from my past, guide me in my present, and help me to trust you with my future. I confess this with my mouth and believe it in my heart. I'm yours Lord, now and forever. Amen."