Some of the themes have rounded profile picture, some themes don’t. If the demo has rounded profile picture, you just need to crop your photo to 1:1 resolution, using your phone image editor (vsco, snapseed, or instagram) and upload the image to your wordpress library.
Upload your image to your media library and copy the URL
Copy the image URL
Go to Appearance –> Widgets –> Footer 1 or Appearance > Customize > Widgets > Footer 1 (editing from both pages will work), Select Skyandstars : My About Me widget and add to Footer 1 widget area. You can move the widget to other widget position too (for example Footer 2 or Footer 3)
Paste the image URL to this field and fill the rest of the fields