That video was published on Aug 7, 2015. Things change in 2 years, including MPLABX/MCC. I'm sure they have a user manual for MCC. It would be quite odd to have a big Generate button that does nothing.
I haven't used MCC in a long time, and have it uninstalled so can't help much more. I have a hard time following most Microchip code, including MCC generated code, so I just look at the datasheet and do my own thing.