The instructions are mostly generic as VS 2012 is independent of SQL Server.

You can follow the instructions here: http://www.codeproject.com/Articles/20987/HowTo-Install-the-Northwind-and-Pubs-Sample-Databa if you don't feel confident to use the SQL Script files (.sql).

I hope you have less problems than the ones you had installing SQL Server.

I wonder how did you know that I'm a native spanish speaker (maybe my accent :-P) as there's no information of that on my profile. BTW, 9000 words is a great vocabulary for someone who "has learned just a few".