Console app in linux for ARM_x32 using LLVM/clang

I need to write a console app that displays a "hello world" message upon startup, running on Linux on an ARM_x32 processor hard float using LLVM/clang. I need to send the entire project in an archive, which should be assembled and compiled, preferably in the Windows environment via cmake. The program must be built in Release mode and have dynamic linking. The size should be less than 20 kilobytes. Compatibility with Libc version 2.19 and higher is also required. ssh.

I've already done the cmake project and downloaded clang in my linux(ubuntu). What should I do now?