Since the two pieces I've uploaded to the site - Niagara Waltz and Death March - both call for pedal, I thought I'd post some tips on using the sustain pedal here. The Performance & Practice tips for both pieces do include this information, but I'm providing a more general overview here.
The sustain pedal is the pedal on the extreme right. As the name suggests, you use it to sustain or prolong sounds. This can be especially useful when you have to move from one position on the keyboard to another, but want the first set of notes played to keep on sounding when you lift your hand.
In music that simply contains the instruction "con pedal" without specific pedal markings to indicate on which notes you change pedal, pedal every chord change. If you're unsure of how to figure out chords in music, pedal every measure.
First play the note, and then depress the pedal with your right foot. If you find yourself wanting to depress the pedal at the same time as you play the note, force yourself to slow down, and divide each beat into eighth notes and count 1 &. Play the note on the count of 1 and depress the pedal on the count of &. As you get better with your coordination, you'll find yourself depressing the pedal immediately after you've played the key - on the count of e if you were counting 1-e-&-a, for instance.
In some of my pieces, you'll need to move from a bass note to a chord or harmonic interval about an octave above the bass note. In this case, after you've captured the sound of the bass note with the pedal and BEFORE you need to play the next set of notes, lift your hand off the bass note and position them over the next set of notes you need to play.
For instance, if you're called upon to play a chord at the count of 3, get ready to move on the count of 2, and actually lift your hand on the count of &. Keep your foot on the pedal.
Changing pedal can be tricky. You want to clear the sound from the first notes sustained, and then capture the sound of the next set of notes that need to sustained. So, follow all the steps above until you come to the part of the music where you need to change pedal. At this point, lift your foot off the pedal just as you play the key, and then immediately after you've touched the bottom of the keyboard, depress the pedal.
So, if you had to change pedal at the count of 3, you'd play the note, simultaneously releasing the pedal. Then on the count of &, you'd depress the pedal again to capture the sound of the note you'd just played.
Again, counting in this way is just for practice until you get used to working with the sustain pedal.
Experiment with the pedal to see how far you need to go up for the sound to clear. You don't have to lift all the way up to clear the sound from the previous notes. Make sure your heel is firmly on the ground at all times.
In my pieces, the sustain pedal helps you play the L.H. in a smooth, legato fashion. Play the L.H. chords and make a note of the sound. When you use the pedal, listen for any muddying of sounds or a reverb effect. That will tell you, you're not clearing the pedal quickly enough as you change.