After you register, you can either apply to published opportunities that you will see on the main page or wait to be contacted by an organisation with an offer. Once you are contacted, you can either accept or decline the offer. You are free, of course, to ask for more information and discuss the opportunity with the organisation directly. If you are matched by a host organisation, you may need to find a supporting organisation in your country. You can look for it in the database of volunteering organisations. Sometimes a host organisation helps you with finding a supporting organisation.