any body help me in session

Question

hi i m attaching a file in this first student login and redirected to default2.aspx page here he/she find a button to start his/her test . i just wanted that as student click this button student redirect to default3.aspx page and his session values maintain the next page and his session time display on those pages(you can use any duration in minutes) and if session time left only one minute a message display to the student so that he/she save their answer