To turn off a note, click on it. To edit an envelope , clock on the boxes at the top to select the parameter, for example frequency, or amplitude. Then click and drag points to move them. Click between points to add new points. Shift-click on a point to delete it.
Time is represented by the horizontal axis.
The parameter value is represented by the vertical axis. There is a maximum time value for the entire envelope. If you cannot add more drums, delete one to make room. Type in the text field at the bottom of the screen and hit enter to chat with other performers. Experiment and have fun.