A Needs Assessment starts when you ask yourself where you are and then determine where you want to be. It's not just the what, but the who, how, why, when and where of how you will get it done. It is a simple analysis of your current situtation and a basic outline for how to get to where you want to be. Imagine that it is a roadmap towards the future.
You want to plan the process otherwise you can miss vital problems with your ideas. It is very easy to say you want to triple sales next year, but without a plan, you aren't going anywhere. A needs assessment is what you need to ensure success.