HELP PLEASE!!

I recently purchased the software Sonar Proffesional. I just set up my recording interface. When I record one layer it is fine, but as soon as I start to record a second layer and re-records the layer that is playing back to me so I know what to sing along to. 
 
Can anyone help me figure this out or even give me some starter tips as I have never used this software or recorded myself before?
 
Thank you in advance!

Hello  curley,
 
I'm not quite sure I understand your question. If you want your first recording to play while you sing into a second recording, you would record your 1st take on track 1 and then your second on track 2. Is that what you mean?
 
If you are new to Sonar you should take some time to watch some of the videos on Cake TV. They can be helpful. I also highly recommend Groove3.com. They have a great set of videos on Sonar. You can either buy one or sign up for a month and view all the videos you want for that month. It might be very helpful.
 
Dave

So my issue is I am recording through a mixer, lets say I record me playing guitar for the song. After recording that section I go to record in a new track below it. but what happens when I record me singing, the program re records the guitar layer as it plays back. So essentially I am recording the guitar in one recording, if i were to make a new track, press record and just listen to the guitar play back whilst in recording mode the guitar will double over so there is a recording on the original track and then also the exact same recording on the new track.

It sounds like the first track is always armed for recording.
 
It is only going to record a track that is armed.
 
When you record the 1st track, the guitar, arm that track for recording, then record the guitar track. Disarm the first track, then arm the second track and record yourself singing.