The first thing you need is to register for an account.  An account allows you use the API.  You need a valid email address to register, and once you register a confirmation will be sent to the email you provided.  It will contain a link that you need to click-on/follow in order to activate your account.  Only after your account is activated will you be provided with API keys — one for reading and one for writing — which will allow you to interact with the Sensorcast system using the API.