These are the links to some excellent resources in this forum related to Matter:
In addition to Hubitat C-8 hub, you will need at least one more Thread Border Router device - for example Apple HomePod Mini, or Amazon Echo (4th generation), or Google Nest Hub, etc...
Then download the Nanoleaf mobile app, update the firmware, and add it to the TBR device that you have.
Pairing the Nanoleaf Thread bulb to Hubitat will be the last step.