OK so to set and read variables from the current session
String Myvar =(string) System.Web.HttpContext.Current.Session[“MyVariable”]
To set
You can access the session by implementing IRequiresSessionState interface in your class.
This is a flag interface, so you dont need to implement any extra code.
When you implement this asp.net will know that you want to access the session.
public partial class YOUR_ASPX: System.Web.UI.Page , IRequiresSessionState
{
... your code
}