Absolutely! Beware, however, that you will probably get unwanted feedback from the amplifier if you are using an electric/acoustic guitar. Acoustic amplifiers have circuitry built into them to help negate feedback.
boredom is a harsh mistress for me to answer this but hey that doesn't mean I'm not gonna help you. step 1 - plug in the amplifier to a wall step 2- plug in a patch cable into your electric guitar...