Another roll on the rudiment list that you are going to experience is a closed or multiple bounce roll. Sometimes it's called a buzz roll. Basically what it is, instead of open strokes or wide open or individual playing you're going to have a series of buzzes on each stick as you alternate sticks.
So the best way to start is to discuss the fact that your fulcrum point on your hand needs to be a little bit tighter. The pressure usually goes up a little bit more toward the front part of your hand. Basically what you want to do is close in that fulcrum and keep those fingers lined up down your hand so that nothing flails out like a pinkie or any other finger - we often call this drinking tea.
What you want to do is use a full stroke and set the stick back into the snare drum head. When you do that you're trying to obtain a series of buzz strokes from each stick as you move them and as you alternate them. So, one stroke would sound something like this.
It's almost like you're stamping your name into the drum head and you're leaving the stick there for a second to obtain those buzz strokes. Now, as you alternate hands you'll hear it's going to turn into this loud buzz roll or closed roll.
Now there are different dynamic levels of the buzz stroke roll that you can work. If you want to get a little quieter or pianissimo you want to get up toward the top of the drum. And as you get louder you want to get toward the middle of the drum without staying right in the center of the drum - you want to stay a little bit outside the center of the drum.
Whichever way you do it you want to keep it clean with all those buzz strokes. You want to move those arms in time and you want to move up and down the drum to create the dynamic level of your buzz roll.