Authorization and User roles

Question

hey guys.. i have two forms and user can make adding, deleting, editing processes if he/she wants..but now i want that not everybody can do these things and can see the all buttons or other tools on the form..i want only the people who has administrator authorization can see that important points..the thing is i didnt do something like that before and i dont know where should i start..is there anyone who has small sample code for that or any other help will be appreciated