It didn't exist 5 years ago, so you must have tried one of the 3rd party crappy attempts at making a GUI. Sadly, it's difficult for Octave to shake off its reputation.

Try the GUI again. Here is a web version of it that is almost identical to running it on your own desktop:

https://www.rollapp.com/app/octave

This web version is based on Octave 3.8.1, though. Octave 4.0 has a much better version of the GUI:

https://en.wikipedia.org/wiki/GNU_Octave#/media/File:Octave-...

If you have Windows, try our installer:

https://ftp.gnu.org/gnu/octave/windows/