The Dbdim chord is a great workout for your pinky! We start by putting the index finger on the first fret of the C string. We then use our pinky to play the fourth fret of the A string. This will feel awkward to hold the ukulele with your thumb and those two fingers, the more strength you have the easier it will be. Make sure to keep the fingertips straight up, that way you won’t touch other strings and dampen them.