If the server is currently running, copy and paste the keys into ImportKeys.txt and use the web panel. The keys will be individually compared to make sure there are no duplicates to existing keys. Each key that passes inspection will be added to the list and autosaved to Dynamic/RegistrationKeys.txt
If the program is NOT running, you may add keys directly to the Dynamic/RegistrationKeys.txt file. They will be loaded when the server is next launched.