Intonation

Hi,
I find difficulty in understanding intonation espicially in drowing lines up and down,
I understand the meaning of the types of intonation but it is difficult to apply on sentences. Can you help me?

What sentences do you have in mind?[YSaerTTEW443543]

TOEFL listening lectures: A university lecture by a professor of Physics[YSaerTTEW443543]