how is the sundial made and why? Please gv reasonable answers.?

Answer 1

You can draw it on the sand at the beach. Stick a stick in the ground. A Popsicle stick will do and put marks where the shadow falls at each hour. The next day if you go to the same place you'll have a functioning sundial telling the exact time.
Alternatively you can use any flat surface you can leave marks on and any object that would cast a shadow. It can be on the ground on a piece of furniture or on a wall as long as the sun sees it. Check the wikipedia link for history if you are interested.

Answer 2

It was made to tell time.