Enterprise Application in .NET

can you give me some hit or give me explanation how to create Enterprise App in .net, and how projects type use or how should be structure of this projects? I newbie in EE and I read about it, but for me is the best explanation on real world example. My idea about EE solution structure in .net is that:

• Data Tier (project type => class library)

  • database access classes
  • some mappers (I am not sure if I could use data mapper pattern or else? Is good idea?)

• Bussiness Tier (project type => class library)

  • entities which wil lbe mapped in data mapper in Data Tier
  • and some application logic
  • service tier (I am not sure if it should be individual tier, or subtier of bussiness tier - I want to use WCF)
• Client (project type => WebForms / Android / WPF / ....)
  • will be communicate with bussiness tier over WCF

Is my idea good? I will be gratefull for any explanation or hint how patterns could I use with respect my low knowledge. I have requirements to use 2-3 patterns, becouse is school project. Thanks for answers