Connect any necessary equipment to your computer. If recording audio from a tape player or record player, you will typically need a 3.5mm RCA cable (the red and white RCA plugs connect to your input device, and the 3.5mm plug connects to your computer via the "Line-In" or headphone port). For instruments, consider using USB instrument cables or connecting an audio interface (external sound card for instrumentation) to your USB port.
Open Sonar and click the "Options" menu at the top of your screen. Select "Audio" from the list and choose the "Drivers" tab. From the "Input Drivers" menu, select your device. If you wish to record using your computer's internal microphone, skip to the next step.
Create an audio track. Click "Insert" on the menu bar at the top of your screen and select "Insert Audio Track" from the drop-down menu. You can also right-click anywhere on your project window and select "Insert Audio Track" from the pop-up list. Your track is the space on which your recorded sound waves appear, and resembles a long horizontal bar.
Click the "Record" button to initiate the recording process. The button appears at the top of your window and looks like a black circle. When you finish recording your audio, press the "Stop" button at the top of your window, which looks like a black square.
Create additional tracks to add layers to your audio. This is particularly useful if recording original music. For example, if you recorded a lead guitar riff on your first track, you can then create a second track for recording a rhythm guitar riff. Create as many tracks as you need.