First try
File:Music_project2.maxpat
I have to add others musical instuments
Second try
The toggle button sends a signal to the slider object that allows you to set the miliseconds between the creation of each notes (I chose 500 by default for each). It then sends a signal to the random object to which I have set a limit of 120 like all the others so that the selected number is between 1 and 120. I then display this number and with the help of “makenote” (to which I limit a velocity of 120 and a duration of 100) I create this note.