Automatically open google chrome, click button, and close chrome C# WinForms

I've got a task as I've written in subject. I need to open google chrome with a web page and then I want to click button and close chrome. I want it in a Windows Form .net 4.0 and written in C#. I've tried to do something like that:

System.Diagnostics.Process.Start(@"chrome.exe", "webpage");

and this is working well, but I have no idea how to force application to click button on this page and close chrome.

Thanks for any help