Brand Definition is all about identifying the purpose and values that drive your organisation, so that you can use them to attract your customers and stand out from your competitors.
After you have defined the purpose and values behind your organisation you need to communicate them. Brand Development is about deciding how you look and how you behave.
Brand Delivery is about bringing your brand to life and engaging with your audience. You need to change the way they behave, so they choose you and not someone else.