Select a soft-sounding pad or instrument from the sound bank in your keyboard.
Put an instrument that is slightly louder or more forceful on a separate track or channel in the keyboard. This sound can range from strings to a choir to a synthetic lead.
Layer your two instruments by selecting the "Layer" function, which should have its own button on your keyboard. This will allow you to hear both instrument sounds at once. If you have a generic keyboard without multiple tracks to put different sounds on, it should still have a "Layer" feature that will allow you to mix two sounds at equal volumes.
Lower the volume of your louder instrument's track until the two sounds blend together. This can be done by sliding the fader in your keyboard's mixer, which should be accessible by pressing a button labeled "Mixer."
Continue adding and layering tracks with different sounds until you are satisfied with your creation.
Record a drone of your ambient guitar playing or created keyboard pad into your loop machine. A drone simply is a single, unchanging chord that represents the key your song is in. You will need to record and save a drone loop for every key in which you will play.
Select the drone that matches the key of the song you will be playing from one of your recordings, put your volume pedal to the upper position and begin the loop. Because pedals are operated by foot, you can control your guitar playing and pad presence simultaneously without ever stopping one or the other.
Lower the volume pedal to subtly fade your pad in and begin playing your guitar. Fade out your pad at any desired times throughout your song.