I can’t see ( from the tutorial either ), how to set my audio device as input for recording. Thanks. 
In Cubase, go to ‘Devices’ menu and click device setup. Click VST audio system and ensure the Focusrite USB audio driver is selected. Click apply.
Once done, come out and go back into devices menu and click VST connections. Make sure that you have 2 stereo inputs and 2 stereo outputs set up as buses.
also, in windows, right click the speaker icon in the system tray and click recording devices. Set your focusrite line in as default. Similarly for playback devices, set line out from focusrite as default.
Thank you - that’s helpful. I don’t have Windows ( system tray ), for the final part, "right click the speaker icon in the system tray … " What do I do on Apple Mac v 10.9 please ? How do I delete unused inputs/outputs, in VST Connections please ?
The last bit (about the default playback devices in windows or mac) is only necessary for sound in and output for software that doesn’t use the focusrite ASIO driver. If you start a random youtube video and you have sound then you can forget about that last bit.
It would help if you mentioned which version of Cubase you are using, but usually your VST connections look something like this:
(ignore the red circle, this is not my image 
).
To delete a bus, just click on the bus name and press delete on your keyboard. In the image, this would delete ‘Stereo Out’ 4’. I realize this image shows the outputs, but it works exactly the same for inputs.
You don’t say what you are recording and which inputs you are using for that. If you are recording a mono source (mic, guitar etc), create a mono bus and assign the input to it you connected your instrument to. If it’s stereo (keyboard, e-drums etc), same thing but with a stereo bus obviously, and you assign 2 inputs to it.
To record, you create a new audio track in your project window (stereo or mono as required). As input to the audio track, select the bus you just created. Arm the track for recording, hit record and you should be recording what’s going into your selected focusrite input.
Note that if you have the full Cubase and intend to use Control Room, then set any connections on the Outputs panel, like Stereo Out, to not connected. This then becomes the target for all mix rendering to file.
Then use the Control Room panel to set up busses for your physical (on audio device) speaker, phones and cue output connections.
For details, see the Operation Manual:
a) VST Connections section on page 32.
b) The Control Room (Cubase only) section on page 211.
My advice is that you at least read the first paragraph under each section and heading in the Operation Manual, so you are at least familiar with what Cubase facilities and functionality are available and where to find them in the manual if you need to get further details.