Hi and welcome to the forums!
Did you set the M50 for both Enabled and Control ?
If that is gobbledegook to you, download the free User manual, watch some of the many free videos and learn about setting up MIDI controller and keyboard devices.
With any luck the guy who wrote the manual will be along to tell you where to look shortly!
He keeps funny hours though due to living in the antipodes....
And of course if you are still stuck, come back and ask some more.