Excel scatter diagram

Given the following data, 1) how do you make Excel create a scatter diagram for you?  2) If you were to draw a line through the points, how straight would the line be?  3) What is the coefficient of determination - r2 for this data, and more importantly,  4) what does it mean?

# Employees # Orders received
1                12
2                10
4                 9
3                11
5                12
4                15