You mean you want to see what's in the database?
If so : after you install nopcommerce you will have a file named ConnectionStrings.config ni nopcommercestore directory.
Open it you see something like that:
<connectionStrings>
<add name="NopSqlConnection" connectionString="Data Source=sqlserver;Initial Catalog=nop1_6;Integrated Security=False;Persist Security Info=False;User ID=username;Password=pwd;Connect Timeout=120" />
</connectionStrings>
Open sql management studio om server name write your server name - in the example above : sqlserver
in Login write (as in example above): username
in password write (as in example above): pwd
When it opens click on databases on the tree in the left and then click on your database name (in the example above nop1_6)
Then click on tables - you will see all the tables.
To open a table right click it and select Edit Rows