Let us have a look at the interface first. The app highlights the key, which consists of seven chords: three major, three minor, and one diminished chord.
These chords will sound great together. A good base for your song!
It is one possible way to find chords by tapping different chords in the wheel until you find something you like. For example, you've found four chords you like, then assign them to a line of your song — for instance, the "Verse".
It may sound pretty awesome to use chords that are not in the key! Of course, you can do that as well with the app. To do so, tap on the "Modal interchange" button. The app will immediately suggest a chord for your song.
Of course, you can edit particular chords and add optional tones, mute them or select a different bass note for them.
You will have a little identifier which indicates whether the chord you are editing is within the key and if not, how many tones are out of the key!
If you want to add another chord to a bar and adjust the length of a chord, you can do this in the "chord-length editor".