How to handle multiple windows in selenium?

You can do something like this

WebDriver driverOne=new ChromeDriver();  
// navigate to your desired URL
driverOne.get("http://www.yourwebsite.com/");

// Do your stuff and copy the new link
// string newURL;

WebDriver driverSecond=new ChromeDriver(); 
driverSecond.get(newURL);

driverSecond will have a focus on the new window and once your actions are complete close the driverSecond.

In Selenium 4 (currently in beta), you the following will open a new window then automatically switch to the window:

  @Test
  public void openNewWindowForTestProjectBlog () {
    WebDriver newWindow = driver.switchTo().newWindow(WindowType.WINDOW);
    newWindow.get("https://blog.testproject.io/");
    System.out.println(driver.getTitle());
  }

//assume - multiple windows are opened by clicking link or a button.    
Set<String> windows = driver.getWindowHandles(); 
    
    for (String window : windows) 
    { 
       if (driver.getTitle().contains("***Something that is on new window***")) 
          { 
             driver.switchTo().window(window);
             //To get title of new window
             System.out.println(driver.switchTo().window(window).getTitle());
          }
    }