The buttons on this screen are divided into four categories of patterns, in four columns headed Basic, Classical, Romantic, and Modern. Clicking any button will generate a new track in the style selected and based on the chords entered. This screen will close, and the tune will start playing with its new accompaniment.
The default instrument for the accompaniments is the grand piano (except for a few special cases where the instrument is fixed for the pattern, such as the harp arpeggios). There is a drop-down box at top left, with which you can change the accompaniment instrument.
Optionally, you may add a double-bass line to the accompaniment, either bowed (by clicking the option marked 'arcato'), or plucked (by clicking the option marked 'pizzicato'). There is an option box which selects that this bass note be played on 1st beat of every bar only, or on odd beats, or on every beat. For example, if the music is in 4/4 time, then selecting odd beats will give a bass note on the 1st and 3rd beats of every bar.
At top right of the screen there is a slider with which you can control the balance between your tune and your accompaniment. Moving this to the left will make the accompaniment quieter, and vice-versa.