Most Quirksmith finger rings are adjustable by design. This means that the end of the ring is kept open, so that it can be adjusted based on the size of your fingers.
The video below explains how to carefully adjust the size of your ring.
Here are also step by step instructions to do the same:
Try wearing the ring as is. If it feels small, hold the ring from the center of the ring shank (or band), and slightly pull the open ends apart
Try wearing the opened ring again. Repeat step 1 if the size still appears small.