You can switch between windows as below:
// Store the current window handle
String winHandleBefore = driver.getWindowHandle();
// Perform the click operation that opens new window
// Switch to the new window opened
for(String winHandle : driver.getWindowHandles()){
driver.switchTo().window(winHandle);
}
// Perform the actions on a new window
// Close the new window if that window no more required
driver.close();
// Switch back to the original browser (first window)
driver.switchTo().window(winHandleBefore);
// Continue with the original browser (first window)