The YouTube app has an icon with a white triangle inside of a red rectangle that resembles a TV screen. Tap the icon on your Homescreen to open the YouTube app. Your profile picture is the circular image in the upper-right corner of the YouTube app. This displays Account menu. Your profile icon is the circular icon that appears at the top of the Account menu on the left side. The gear icon is to the right of your account name below the banner at the top of the page. This displays the "Pick a photo" menu in the pop-up. You can either use your camera to take a new photo, or upload a picture from your gallery or camera roll. Use the following steps to take a picture or choose a picture.   Take a photo  Tap Take a photo. Use your camera app to take a picture (you may need to tap Allow to give YouTube permission to access your camera). Tap Ok or Use Photo. Drag photo so that it is centered in the square. Tap Save or Use Photo     Choose a photo  Tap Choose from your photos. Tap a photo to select it. Drag photo so that it is centered in the square. Tap Save or Use Photo

TL;DR in Vietnamese:
Mở YouTube. Nhấp vào ảnh đại diện. Nhấp vào ảnh đại diện một lần nữa. Chọn. Chọn trong ảnh đại diện. Chọn Take a photo (Chụp ảnh mới) hoặc Choose from your photos (Chọn ảnh có sẵn).