C# 2010 how to create dll

Question

I am working in Visual Studio 2010 using Visual C# 2010 WINFORMS, Framework 4.0, Oracle 11Gr2, on Windows 7 OS. I have created a folder in my project called Function Management. I want to put all my functions here and reuse them. Can anyone tell me how to create a .dll for each function and put them in the Function Management folder? I found some examples on MSDN but I found them lacking. Thanks in advance.