Dataset dataadapter in C# visual studio 2010 dot net

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C#

Friends,
I bought a software without "customer support after sales", so I am struggling to rewrite some of the codes in the C# project.
I have the Admin Page(AdminLogin.aspx)
I have the following Code which is redirected from this Admin Login Page(say AdminLogin.aspx/adminlogin.aspx.cs):

The following code has to do the validation of Admin part:

public partial class AdminAccount : System.Web.UI.Page
{
Registration_DS.REGI_SELECTDataTable RDT = new Registration_DS.REGI_SELECTDataTable();
Registration_DSTableAdapters.REGI_SELECTTableAdapter RAdapter = new Registration_DSTableAdapters.REGI_SELECTTableAdapter();
protected void Page_Load(object sender, EventArgs e)
{

}
...
.....
.......
I want to know what this line is and what it says....!

Registration_DS.REGI_SELECTDataTable RDT = new Registration_DS.REGI_SELECTDataTable();

I guess it is DataSet and DataAdapter - but I don't know to rewrite the code.
There are stored procedures(SQL server 2008) namely REGI_INSERT,REGI_SELECT etc
I believe that there is no dll files or any 3rd party API etc.,
so please help me to fix this.

What I have tried:

I tried nothing. But I wrote some simple code to validate Admin Login and list Members registered in the site to approve etc, which is irrelevant to this question, Sorry.