Connect an audio interface to your PC. Typically this done with either a Firewire or USB cable, depending on the interface's make and model. The interface converts the audio signal from your guitar into a digital signal that Anvil interprets. The better quality your interface, the better sound quality of the guitar. Recording at line-level, rather than via a microphone in front of your amp, is preferable when using basic software. While microphone recording is ultimately superior, you need an expensive microphone and an acoustically treated room for it to be worthwhile.
Connect a quarter-inch jack instrument cable to the "Input" jack on the front of the audio interface. Connect the other end of the cable to the guitar.
Open Anvil. Double-click on the desktop and wait for it to load. Click "File" and select "New Audio Track." Opening audio as opposed to MIDI assigns the audio interface as the primary input device. Click on the box where it says "Audio 1" and type "Guitar 1."
Audition the sound level. Play the guitar as loudly as you intend to record. If the volume unit light flashes on the audio interface, this is a warning that the signal is too high and will distort on recording. Turn down the "Gain" dial. Tweak the gain so it's as loud as possible without distorting; this way, you have a clear, yet undiminished, source signal.
Click "Record" and play your guitar part. Once finished, open a new audio track, name it "Guitar 2" and record the same guitar part so you have a stereo pair. This will give a sense of depth and clarity to the guitar sound.
Press play so you can hear your subsequent adjustments as they happen.
Click on "Guitar 1" and click "Effects." Select "Reverb" from the drop-down menu. Reverb adds ambiance to an audio track. Adjust the "Depth" dial on the reverb interface to tweak the intensity of the effect. Don't add reverb to "Guitar 2," as this will create a muddy sound. Free software such as Anvil is characterized by low sample rate and lower fidelity. By adding reverb to one half of the stereo pair, you create a smoother, more ambient sonic result that goes some way to disguising the fact that you used free software to record.