Watch these videos of real Russians saying the tongue-twisters included in your book! Mastering Russian tongue-twisters takes practice and lots of repetition. Remember: Повторение мать учения! (repetition is the mother of learning)
Шла Саша по шоссе ...
If you're interested in Russian popular culture, take a look at these music videos and see what words you can pick out. If you copy and paste the title into your search bar and then type the word "текст" (which means "lyrics" in this context), you can try to follow along.
Первое видео: "Самый Счастливый Человек" – Каста
Второе видео: "Солдат" – 5nizza (пятьница)