To play the drums, all you have to do is tap them. For the electric guitar, you can only be using a computer, or a keyboard. To play E, for example, you would click the letter 'e' on your keyboard. It plays one octave, from C to C. To play low C, just press 'c'. To play high C, you would have to press the number 2. (The speakers do nothing.)
Thanks to Apple's Garage Band for giving me this idea.