Open Sketchware pro.
Go to developer console.
Click on Event manager.
Click on Activity events at the top.
Click on add icon.
Fill the all fields by copy paste as follow or filling in the fields as shown in the image.
event name - onStartActivityManually
description - onStartActivityManually
parameters -
spec - onStartActivityManually
event code -
public void startManually(){
%1$s
}