If you're upgrading from an earlier version of AspDotNetStorefront, one thing you'll notice is that you no longer have an admin login page.
We removed the signin.aspx page (which is what you see in any version prior to 10) from the site files to consolidate the log in functionality. This removes an unnecessary step and speeds up the admin login process. If you enter your admin URL, the site will take you to it's front end login screen. This redirect is normal. Once you've entered your admin credentials, the site knows to take you to the admin console. Try it!