Several editors are installed by default.
Download and install Terminal Emulator.
editors you can use:
The use of vi is very limited, however, because there is no way of how to enter Esc character using the virtual keyboard. Also the terminal itself is non-standard and the $TERM system variable is not set. The first step would be to write /etc/termcap entry describing the terminal.
The Unix system was originally developed on machines with VERY primitive and extremely slow terminals, sometimes even teletypes attached, so most of basic commands are very short. You will deeply appreciate the fact when you try working with the virtual keyboard ;-)