First, read the English article below.

Click the Apple logo in the top-left corner of the screen. A drop-down menu will appear. It's near the top of the Apple drop-down menu. You'll find this computer monitor-shaped icon in the upper-left side of the System Preferences window. It's at the top of the page. If you want to extend your desktop using the second monitor, make sure that the "Mirror Displays" checkbox is unchecked. If you want to display the same content on both monitors, you can leave the "Mirror Displays" box checked. If you want to use the second monitor as your main display, you can click and drag the white rectangle at the top of one of the blue displays onto the second display. 

Now, please write a short abstract for it in Hindi. Abstract:
एप्पल मेनु ओपन करें: System Preferences… क्लिक करें: Displays क्लिक करें: Arrangement टैब पर क्लिक करें: "Mirror Displays" बॉक्स को अनचेक कर दें: आपके डिफ़ाल्ट डिस्प्ले को चेंज करें: