There is no simple answer to this question. The first thing to do for any application, is to analyse the requirements, such as:
- data: what type, where to store it, how to store it
- business requirements: what does the application need as inputs, outputs, how are they transformed
- user interface: is it desktop, web based etc.
and any other issues relevant to the problem.
When you have a more specific technical question then you can come back here and try again.