I'll try help you out at best as I can despite your terrible description of the problem.
I'm assuming your are referring to playing Graal on 3G/4G Mobile data, if so you should be able to do this when ever you want as long as you have strong enough connection.
If this isn't working for you then you might have at some point disabled your Graal app from using your mobile data. To fix this go to settings>Graal Classic >use mobile data , this should be on.
If that isn't the cause of your problem then it might be the strength of your signal, the better your reception the better your data will run so make sure your in a area of strong signal.
If non of that is your problem try redownloading the app