You can change your profile picture (avatar) by doing the following:

  1. Tap on the profile icon at the bottom right of the screen to open your profile screen
  2. Tap on the 3 dots at the top right of the screen
  3. Tap "Edit Profile"
  4. Tap on your avatar image
  5. Tap "Choose photo" to choose an image from your camera roll, or "Take Photo" to make a new one.
  6. Tap "Save"
  7. Tap the Back Arrow and you're done