In addition to the documentation mentioned by Shijin, we also offer free video training to get started on Sugar 7 with different tracks targeted towards, end users, admin users, and developers.
The video training mentioned by Chris was good. Is it possible to get an experienced developer to visit my company, that I can quiz for a day? I went on one of the developer courses in London, but since there was so much to cover, it only scratched the surface of each topic. I'm struggling to get some specific questions answered in the forum here, I think perhaps I'm missing some core understanding in the Sugar architecture. I've successfully implemented dashlets and logic hooks by following online guides but am struggling with extending the UI.