What should you do?
God is preparing wonderful blessings for you too, if you choose to say NO to dirty thoughts and pictures.
When you sow a THOUGHT, you reap an ACTION. When you sow an ACTION, you reap a HABIT. When you sow a HABIT, you reap a CHARACTER. When you sow a CHARACTER, you reap a DESTINY.
The Lord Jesus was tempted exactly like you, but He never sinned. That is why He can help you. Maybe you sinned against God by looking at dirty movies or sexy images, and maybe you felt you could never give up this bad habit.
If you have read the Bible text suggested on page 3, you found out that Joseph ran away from temptation.
You cannot run away from your phone, but you can close a dirty page immediately. You cannot run from school when the other boys are looking at dirty magazines, but you can firmly say that you do not want to look at them, even if they will laugh at you. God blessed Joseph for choosing to remain pure.