How to tie in a VB.net login page with a sql user and Web.config in vb.net

Hello,
I have a typical login page in vb.net (Asp.net). It checks a sql table for a user/pw. If admin1 user they get directed to admin page. if not, they go to basic users page. I put this below code in my web.config page in the testlogin folder. (which I want to be secure, only admins can get to this page)
I don't want someone to be able to go to ww.mywebpage.com/testlogin/securepage1.aspx and view page.

How do I get the user "Admin1" from my login page that is validated in sql and pass that on and have the web.config grant admin1 access to securepage1.aspx
I am not using roles from MS SQL

<?xml version="1.0"?>
<location path="/testlogin/securepage1.aspx">
<system.web>
<authorization>
<allow users="Admin1"/>
<deny users="*"/>
</authorization>
</system.web>
</location>