Connect a MIDI controller to your computer. You can use any keyboard with MIDI ports as a controller, and you can find inexpensive MIDI keyboards at music stores and even toy stores. The keys simply allow you to control or play the digital instruments in SONAR. To establish a connection, connect a USB MIDI adapter to your computer's USB port. Then connect a MIDI cable to the "MIDI Out" jack on your MIDI controller and the "MIDI In" jack on your adapter.
Open SONAR and create a new MIDI track. A MIDI track is a recording space on which you can create digital music loops. To create your track, right-click your mouse anywhere on your project window and click "Insert MIDI Track" on the pop-up menu that appears. Your track will appear across your screen as a long horizontal bar.
Click the "Options" menu at the top of your screen and select "MIDI Devices" from the drop-down list. Beside the "MIDI In" menu, select your MIDI source, usually indicated by the name of your adapter or other MIDI interface. If your adapter does not appear on the list, check to see if any software drivers were included with the adapter on a CD-ROM, and install the drivers on your computer. Then return to your "MIDI Devices" menu and select your adapter from the list.
Select a virtual instrument. In order to produce sound from your MIDI keyboard, you must first select the type of sound you want to create, such as a keyboard, drum kit, brass instrument or synthesizer. To select a virtual instrument, click "Insert" on your menu bar, hover your mouse over the "Soft Synths" option and select a virtual synthesizer from the list. From there, navigate the available presets on your screen until you find the right sound for your particular music project.
Begin playing melodies on your controller keyboard. The sounds will transmit through SONAR using your chosen instrument sound. To record a loop, click the "Record" button at the top of your project window and play your music sequence on your keyboard. Press "Stop" when you finish. The "Record" button appears as a circle, and the "Stop" button appears as a square.