The functions found in the sound section of the options menu in Roc will give you some useful controls over each track. These functions will let you modify the sounds in your mix.
Replace sound - This function will open the record module where you can record sounds to use in your mix.
Remove Sound - This function will clear the sound from the mix and leave the track empty.
Rename Sound - Here you can rename the title of any track.
Edit Sound - The Edit Sound function will open the Sound trimmer. From there you can trim the start or end of any sound.
All of these options give you more control over your mixes. Explore all of them to make some incredible beats!