Issue with software and G Code

Hiya everyone, hope there is a simple solution to this. I’m using Carveco Maker and it allows me to do the designs but when I go to produce them I get a message in the right corner of my screen saying something about there not being any G Code. I’ve tried to download the G Code that’s demonstrated on Youtube by Ooznest but I’m not having any luck. Can anyone help me.

P.S I’m not into software so any replies have to be as simple as possible.

Thanks