You have to add the duet-tags manually, before you can use this txt.
At the beginning of the lyric-part, i.e. after the last line that starts with a # (Header-information) you need to add: P1
Scroll down the txt and watch the numbers, that indicate the beginning of each note increasing. Once you come to the point where these numbers are starting with a lower value, add P2 after the line with the highest number and before the line with the low number, since here begins the part for Singer 2.
