Help getting started with Roku devices, including setup, connecting your device to your TV, linking a Roku device to your account at my.roku.com/link, adding channels, subscribing to services, and more.
Can you please clarify the issue you are experiencing? As @renojim mentioned, if you have already setup the Roku device, you will not longer need to activate the Roku device.
If you need to activate a device again, you would need to first try to perform a factory reset on the device. For more information about how to perform a factory reset, visit our Support page here: How do I factory reset my Roku® streaming device?
With more information we will be able to assist you further.