Best approach of web application using asp.net & sqlserver

Question

I am trying to develop a web application using asp.net using C sharp in the front end and sql server at the backend using visual studio 2012 and sql server express edition 2012. The project that I am currently working on is the online blood bank management with admin and user logins. I have my ER diagram, schema with all the tables ( about 20) ready. I am not quite sure how to start? Should I first concentrate just on the tables,populate and establish relationships, then proceed to front end design with the registrations part and everything else or just do both of them parallely? Can someone please guide me through, I am trying to learn application development and this is my first one. Any online resources for similar sample project walkthroughs along with some explanation will be of great help!!

Thanks,
Dimpy