Note tracks store their notes as MAXNoteKeys. As seen by MAXScript, note keys are stored in a MAXNoteKeyArray. The MAXNoteKeyArray for a note track is accessed via the keys property of the note track.
For more information on MAXNoteKeyArrays, see MAXNoteKeyArray Values.
addNewNoteKey <MAXNoteKeyArray> <time> [ #select ]
Adds a new note key to the note track at the time specified. The new note key is also selected in the track view if the #select optional argument is specified. The value for the new note key is a null string.
Time value or number (interpreted as frames)
Specifies whether the key is selected. Read/write access.
String contained in the note key