Type in the serial number of your device which can be found on the back of the hardware token.
For the Yubikey, you can also find the serial number in your WebStore account (Log into WebStore with your NetID, under Order History select your order number. The serial number will be listed under the Installation Key/Code).

After you select Continue, you will need to confirm your token.
For Yubikey:
Insert the Yubikey in the USB port of your computer with the gold button facing up. It will take a few seconds to register the first time. Press the gold button on the Yubikey and it will generate the passcode and log you in. Make sure CAPS LOCK is off when registering a Yubikey.