Three Silent Letters in Hebrew

In chapter four of my Hebrew book, they introduced the equivalent of N and three silent letters. Why does a language need three silent letters? How am I supposed to pronounce it? I understand that a silent consanent lets the vowel speak, but the silent vowel?

Lucky for me, Ronnie is fluent in modern Hebrew and has offered to help. His email tutoring shows his knowledge, but isn’t helping with my pronunciation. I’m certain the people at starbucks are getting sick of my Hebrewathons over lattes.