How To Get Students Attention?

I am a fresh graduate university student in majoring Mathematics Education. In other words, I'll be a mathematics teacher. When I was a training teacher at SMAN 1 Magelang, I found difficulty to get my students attention in the middle of learning. Then, I was being silent for awhile and students would curious what was happened. After I got their attention, I began to continue my lesson. Roseboro,  an educator and writer at Grand Valley State University and Calvin College, gave me 2 advice to get students attention.

1. Students are talking all the time. All you can do is being silent for awhile, then students will wonder what is happening. And when they become quite, you can continue the lesson. DON'T TRY TO TALK ABOVE THEIR TALKING.
2. If it is not about talk, you can give more explanation about the application of the materials. How to solve daily problems by using mathematics.