In this chapter we looked at how to install an operating system (one of Ubuntu or CentOS) and Asterisk itself. We did this securely by installing via sudo and running Asterisk as the non-root user asteriskpbx. We are well on our way to building a functional Asterisk system that will serve us well. In the following chapters we will explore how to connect devices to our Asterisk system in order to start placing calls internally and how to connect Asterisk to outside services in order to place phone calls to endpoints connected to the PSTN and accept calls from those endpoints.