This chapter begins with an example of the features and the usage of the Env-assisted development environment. It shows an example of the Real Time-Thread (RT-Thread) application development process. Menuconfig is a Kconfig-based graphical configuration tool that RT-Thread uses to configure, tailor the entire system, and eventually generate the rtconfig.h configuration file required by the project. RT-Thread provides an online software package management platform where it stores official or community packages. The official packages provided by RT-Threads are hosted on GitHub. RT-Thread provides an ARM vexpress A9 board-level support package simulated by QEMU. Compile and download the project to the development board, then press Reset. The RT-Thread logo and the version information will be printed on the terminal.