The article provides an in-depth tutorial on handling multiple browser windows, tabs, and pop-up windows using Selenium C#. It explains the concept of unique alphanumeric window handles, which are crucial for identifying and switching between different browser instances during automated testing. The tutorial covers various commands such as SwitchTo().Window() and provides practical examples using test URLs, demonstrating how to manage parent and child windows, tabs, and pop-up windows effectively. It also highlights the importance of window handles in Selenium test automation and includes insights into handling browser pop-ups by closing them in a specific order. The article is part of a broader series of Selenium C# tutorials, aimed at enhancing automation testing skills, and is authored by Himanshu Sheth, a technologist with extensive experience in the field.