You could build and compile Octave and spend hours doing this.
Or you can just do this and spend 5 minutes:
$sudo apt-get update
$sudo apt-get install octave
Opens a GUI that says
“Welcome to Octave”
“You seem to be using the Octave graphical interface for the first time on this computer. Click Next to create a configuration file and launch Octave”.
“The configuration file is stored in”