How to begin for asp.net

Question

Respected Experts,

 Please explain to me how to begin with ASP.net. I am confused.

I want to develop a dynamic web site. For which I am going to use a SQL Server database.

Now please tell me what will be the role of CSS and a Master Page. I am confused.

if there is Master Page then why to use CSS?.

Also, browser compatibility issues and please tell me shall I use CSS and Master Page in same project, is it possible?