To play a C7 chord on this type of keyboard, press the C key shown on the diagram with the thumb of your left hand, together with the white key to its left using your second finger.
To play a C7 chord on this type of keyboard, press the C key shown on the diagram with the third finger of your left hand, together with the two white keys to its right using your second finger and the thumb.
The fingered C7 chord is the same for all types of keyboard. To play the C7 fingered chord, use the first, second and third fingers of your left hand.
When changing between the C7 and F fingered chords, keep your second finger on the C key.
When changing between the C and C7 fingered chords, keep your first and second fingers on the C and E keys.