The main window consists mainly of two areas, offering a view on the tracks on the left and a view on the parts to the right, headed by a timescale.
With an empty song, there exist no tracks or parts at startup. Tracks and parts can be added either via the menu "add->track" and the contextmenu "add part" which pops up after clicking the right mouse button on the track name - or just by
doubleclicking the left mouse button into the part area !
You may start with a ScoreTrack. Clicking the right mouse button on the part pops up a menu, offering some editors. Choose the one you like to create your piece of music.