وعليكم السلام ورحمة الله وبركاته
Yes, this is how Salaat-ut-Taraaweeh is performed. A short break should be taken between each set of four Rak`aat. This short break, in Arabic, is called a "Tarweewah" (short period of rest). Salaah of "Taraaweeh" gets its name from this word. "Taraaweeh" is the plural of "Tarweehah".
So you will first make Salaat-ul-`Ishaa, then the 20 Rak`aat of Taraaweeh, and then lastly the three Rak`aat of Witr.
والله تعالى أعلم
والسلام