You create your snare roll. Send to piano roll if it's not already there by right clicking on the snare sound in the step seq. Then in the piano roll go to the little arrow at the top left and click on file.... save score as.... Save it in your scores folder. Then when you wanna use it again go to the scores folder in the navigator on the left and drag it to the channel of your snare in your new song. Bam! There you go.