Before you can register an Application to work with our API, you'll need a Wave Account. If you don't have a Wave Account, sign up now - it's free!
Your API Applications will be associated to your Wave Account. When you first register an Application, you will be able to create an Access Token, which will provide full access to all the Businesses in your Wave Account (so be careful to keep it secret!)
Please note that Wave does not have a concept of a 'sandbox' account, but you can create as many Businesses as you wish within your Wave Account, so simply create a Business to be your sandbox.