Domain names are issued on a "first-come, first-served" basis and the registration procedure is quite simple, provided your chosen domain name is still available (you can check this here for .eu, here for .be and here for .nl extensions). If your domain name is still available, contact a registrar to register it for you. A registrar is a kind of dealer for domain names, who processes the transactions and provides support. Once you have registered a domain name, you will have the right to use it for a period of one year (this can be prolonged). It is also good practice to review your existing domain names from time to time, especially if you want to obtain new domain names when entering new markets.