Did you know that you can combine multiple instruments in our online music creator Roc, to create songs with an orchestra of sounds? Select an instrument from the top of the sidebar, and all the sounds that are contained in it will be displayed below. Pick the sound you want to add to your file and drag it onto one of the tracks. You will see a green box showing where the clip can be dropped and a convenient message will let you know that the sound is loaded on the track. Repeat as needed - you don't have to stick with one instrument.
Now go mix and match sounds and make some incredible music!