G-code is the instruction set generated by the slicer which tells the printer what to do.
The AON-M2 runs using a firmware based off of the popular Marlin firmware project, and many of the G-code commands are similar in functionality, but with subtle yet important differences. Please refer to this manual for all G-code commands to be run on the M2.
While it is not necessary to be familiar with the intricacies of G-code for day-to-day usage, the aspiring power user will find it invaluable to develop a solid grasp of the fundamentals for developmental work, detailed optimization, or advanced troubleshooting.