I need help calling my stored procedure

I am a beginner and using ASP.net, VB.net, and SQL Server.  The name of my stored procedure is AuthenticateThisUser.  I would appreciate any help anyone can give me in rewriting this code to make it work properly.  Please include as much detail as possible.  Part of the code below was sent to me from someone on this site.  I don't fully understand the logic of it though.

The specifics of my procedure are below:

@Username varchar(50),

@Password varchar(50)

SELECT FROM Logins

WHERE Username=@Username

AND Password=@Password

GO

In my ASP page, I have:

Sub LoginUser(s As Object, e As EventArgs)
 Dim blnAuthenticate As Boolean = Authenticate(username.Text, password.Text)
  If blnAuthenticate Then
   FormsAuthentication.RedirectFromLoginPage(username.Text, False) ...