On how to create the radio buttons check out W3schools.com - Forms and their tryid editor
<form>
Male:
<input type="radio" checked="checked"
name="Sex" value="male">
<br>
Female:
<input type="radio"
name="Sex" value="female">
</form>
As you can see both radio buttons have the same name. So just create four radio buttons with the same name. Only the value of the selected button will be sent to the next page.
A good tip is to use method="GET" when you test, then you can see what info is sent on. And you dont need to execute the update/insert part of script until you are sure that things works as you want em too. Or you can just build simple scripts to test out stuff to see how things might work. I usually do this when im unsure about stuff, then i can mess around with it, and it doesnt matter if i do anything wrong.