While the server is rebooting there is an option to press F9 or somthing like that to get into iLO configuration, you will need to configure it there, assign IP address, DNS, user name/password, etc.
After that you can simply go to http:// and access it there, you will be prompted to enter license key there as well.
Make sure you plug network cable to the iLo network adapter and put it in the correct VLAN, etc.
HTH,
Chris