Add chord extensions like 7th, 9th etc.
Use the arrows or tap on the are where the extension is displayed (this can be blurred) in the third column.
It depends on the quality of the chord, in which extensions are available.
- 7 (full diminished)
The dot in front of some entries indicates whether this chord shape is within the key, related to the selected root note and quality of the chord. If there are no dots displayed, the root or quality you have selected is not within the key.
You can also drag the column vertically for quickly change its content.