metronome

 
The only way the metronome would find its way back to the guitar track is via the software mixer. 
Or if you are set for "what you hear" and are actually still using your on board sound card. 
 
Pushing buttons is not how one will learn how Sonar works. You really need to take the time to read the help files. There are plenty of Videos and a  book by Scott Garrigus.  The info on the full versions applies to LE other than missing features, they all work the same. 
 
In case you have not bothered to read the tutorials on how to set up for recording audio, I'll explain briefly. 
Most importantly: 
Make sure you have installed the most up to date ASIO drivers from the Roland web site. I am pretty sure it also includes a software mixer GUI interface. Make sure you follow directions for implementing this first. 
Check in Preferences Audio to make sure only the Roland is your audio device. Obliterate all traces of your on board sound card from within 20' of Sonar. Forget it even exists. 
 
The following is assuming your using a mike into input one (1) of your interface. 
Play hard and set the levels just below peaking. 
You should hear the guitar in your headphones via the Quad captures headphone jack. 
Insert an audio track in Sonar and keep it in focus. (selected)
Press I to open the track inspector.
Open the "input" dialog and choose the quad capture / Left channel Mike 1 input ( the wording will be different but it should be the top of the list) 
Arm the track (= REC) and play your guitar, the tracks meter should move. 
If it doesn't the issue is in your software mixer routing.  
If you wish to hear the metronome during recording then set that using the metronome dialog found to the right of the main display ( tempo/ time etc) 
But now your on your own and you will need to read the manual for your quad captures software mixer routing to set up for the proper headphone mix. It probably has a default setting that says something like- zero latency tracking. 
 
So the only way you could be recording the metronome is your routing your master outputs ( 1/2?) back to the armed track. This is either via the software mixer or your on board card. 

Welcome to the forum.
If you don't have a Roland audio interface, you won't need to download the latest ASIO drivers from them.
If you're using the stock computer sound card, which we think you are, you'll need to check in the sound card recording options that "What You Hear" or "Stereo Mix" is not seletced. It could be called something else, too, depending on the make of the sound card.

You on board sound will not be a factor once you tell Sonar to use the Quad capture. Your problem is you hooked up the quad capture but failed to tell sonar to use it. Sonar will ignore your on board sound 90% of the time. Some people have to disable the on board drivers to avoid them taking over every time you turn your system on. Some times there is no issue at all. 
 
Just make sure you install the drivers for the quad capture, disable the on board in device manager, and then go int sonar and make sure all is good. That all that should be required. 

Ok I had a play around over the weekend. Ive sorted out the internal mic issue by altering a setting within sonar to recognise the quad capture first as suggested by cactus, thank you. I tried loading in the softsynth SI drums. I auditioned the kits all fine but when I dragged a pattern into a song it didn't playback properly so i'm on that tonight.
This takes me right back 15 years or more when I was trying to learn how to use cubase on Atari without a manual.
Ive been out of this for too long but enjoying being back.
All advice is greatly appreciated. thanks again.

Once you insert a soft synth you assign the midi tracks output to that synth. You can change this later.
 
You do need midi data in a track and you can do this by drag and drop , importing or play your keyboard controller in real time and record it.
I make my own drum tracks by starting the song with my singing and guitar to the metronome.
Then I record the drums using either the keyboard or my digital drum kit or both.
With the keyboard it takes a few passes.

Hey glad you got it all working, this is normal and I would think everyone goes through a few weeks of frustration before you can get this junk to run smoothly. It's been 10 years for me and I still fight with it from time to time.
 
Ha ha, Midi cables used to be on the shelf at Radio Shack. And they used to come with a new synth or piano. Now you probably have to order one from Amazon. You'll only need one, unless you plan on playing the sounds in your JV30, But if that's the same synth I think it is, the TTS-1 will blow it away. Oh, that's right, until you upgrade you don't get very good soft synths with LE.
I installed my version on my office computer and I couldn't play any of my songs because of all the missing stuff compared to 8.5 and X3. Go to the KVR web site and looks for a few freebies. 
 
LE is a good start into the world of Sonar but you will outgrow it pretty fast. The layout, recording and editing is pretty much the same as the upscale versions, but it really comes with zilch in the way of VST instruments and efxs. 
Make sure you register with Cakewalk and ask to be on the mailing list. They sent me an offer to upgrade to x3 Studio for only $98. Huge difference, it comes with more stuff than I'll ever use. . 

Right now if you go to the Cakewalk store there is $29 upgrade to X3 ( plain version) 
That's a real deal for LE owners.  Do it!  
Then you can upgrade to full version for $149, so that $180 instead of $ 300 or something.
You can also get the Studio upgrade for $99 right now and I'd go with that. You might not need the extra plug ins that the $80  dollars bring.