MadTracker is, as the name suggests, a tracker. This refers to the way in which the notes are inserted into a piece of music: you have some tracks, and per track one note can be played at a time. In the screenshot you can see the big list on its left, where you can create the piece of music accordingly. You thus have a grid for the notes, which ensures that the notes of different tracks can be played exactly at the same time.

Many alternative software solutions do not use this type of entry of individual notes in tracks, but allow the recording or creation of entire segments, which can then be entered into a tracker-like list without such a grid, and they can be duplicated and moved as desired. Although trackers are rather uncommon these days, I still feel most comfortable with them and use MadTracker for everything related to music.