C# Project - Drop down color changer!

Hi, I'm extremely new to programming in C# and I'm being set tasks. Now, this is my second project I'm attempting to create an application with a drop down list of various default Microsoft Visual C# 2010 Express colors and when a certain color is selected the background of the application is changed to the selected color of the drop down. If anyone could provide some beginners assistance and explain the code to me, I'd appreciate it very much. Once again, I'm just being introduced to C# so please attempt to be simplistic , and helpful!
Thanks!