To install sublime 3 text editor follow the file -> sublime text 3 installation guide.
To build system for C++ and Python in ubuntu. Go to Tools->Build System->New build system and paste the code there(i.e. cpp build system file code or python3 build system file code). Save the file with any name(cpp_bs or python3_bs). Go to tools->Build System and the select your Build System(cpp_bs or python3_bs).