A quick blog post because I wanted to have a audible notification when any prints on my BIQU B1 finished.
In you slicer you can add start and end gcode.
To have a nice short series of beeps at the end of the print use this:
M300 S1600 P50 M300 S1800 P50 M300 S2000 P50
View the reference page for gcode M300 to further tune this to your wishes.