If the fly wheel is going around then the clutch isn't disengaged to wind the bobbin, you need to pull out the flywheel on your model to disengage the clutch for bobbin winding.
Take thread from thread spool across to bobbin winder thread guide, then back to bobbin and thread the tail through the hole on top of the bobbin. Place bobbin onto spindle on top of machine and then push it against the stop to engage the bobbin winding motor. HOld the thread tail up and start winding slowly until the bobbin core has been covered including the starting point. Stop and trim off the thread tail with scissors. COntinue winding bobbin and give the thread a nudge if needed to wind evening top middle and bottom of the bobbin. A good smooth wind is important. Also don't wind at full speed and keep an eye on the thread reel that the thread is coming off, you don't want it bouncing around as this will **** the thread and stretch then relax it affecting your bobbin wind.
Obviously if you know this and the bobbin winding mechanisim is just not working, then it will need a service/replacement by an Elna repair person.