Hello. I am fairly new to this forum. I have cubase artist 8. I have just made my first group track, added all the drum tracks to it via their “send” but I can see and hear that the audio is not reaching the track. Is there another step which I have missed? Many thanks for any help. 
Normally you wouldn’t use Sends to route a Channel to a Group Channel. In the MixConsole’s Routing section you can (and should) change the output routing, which typically defaults to Stereo Out, to your new Group Channel.
That said if you set a Send to go to a Group Channel you should see audio on the Group Channel. If you don’t it is probably because A) the Send has not been enabled, or B) the Send Level is turned all the way down.
A key reason (among many) that you don’t want to use Sends in this manner is that it will have the Channel’s audio going to the Stereo Out through 2 different paths - Channel > Stereo Out, and Channel > Group > Stereo Out. It also, unless you make additional changes, sends the audio to the Group Channel before the Fader. So if you raise or lower the Fader it will not change the level going to the Group Channel.
Aah! Thank you very much Rodger - that explains it all perfectly. I have got it all working now. Cheers!