c#: How to compile an assembly from source code

c#: How to compile an assembly from source code

I have just downloaded an extended version of the Windows Phone ToolKit
from this link, and I don't know how to compile the source code. I used
NutGet to install WPToolKit but this one here can't be installed by it.
But anyway I would love to learn how to compile an assembly from source
code. PS: I am still a beginner.
Thank you.