Open a MIDI-compatible digital audio workstation on your PC. Popular examples include Pro-Tools, Logic and Reason, and free programs like Audacity and QTractor. MIDI simply allows you to control virtual instruments on your screen using external devices, in this case a computer keyboard.
Create a MIDI track, sometimes called an instrument track or software track. Click the "File" menu or "Track" menu on your program's menu bar at the top of the screen and locate the "New Track" option. Select "MIDI Track" or "Software Track," and a long horizontal bar will appear on your screen, indicating a new track, which is simply a blank space for recording audio.
Double-click your track title in the left column to see your track options, which should include a list of virtual instruments. Select any virtual instrument, sometimes referred to as a software instrument or software synthesizer, to create a sound setting for your keyboard. For instance, if you select a virtual grand piano, your keyboard keys will play like grand piano keys.
Locate your MIDI control options and select your computer keyboard as a MIDI controller. Different programs have different methods for accessing this feature. For example, to access this feature in GarageBand, click "Window" on the menu bar and select "Musical Typing" from the pop-up list. In Logic Pro, press the "Caps Lock" key on your keyboard to access your MIDI control feature. Consult your software manual if you cannot find the MIDI control feature on your software of choice.
Download and install a MIDI control audio plug-in or VST (see Resources) if your program does not allow you to use your computer keyboard by default. A VST is a type of audio plug-in designed specifically for digital music software, which allows you to install add-on features, such as MIDI control. For instance, while programs like Cakewalk and Reason do not allow you to use your keyboard by default, they do allow you to access this feature using VSTs.
Play your keyboard keys like a standard music keyboard. The virtual keyboard on your screen will guide you to the appropriate keys, but typically the middle row (beginning with the home keys ASDF) serves as a scale, beginning with C, and the row above contains sharps and flats. Press the "Record" button on the software window and begin playing your keys. To perform live, connect your computer to a PA or other speaker system.