This part really is tricky. I assume they are many way to do it, here is the one I figured out.

Once the outside frame is released (as seen in previous steps), you may pull this frame to see one of the six clips. As shown in picture 1.

Using the nose shape you are able to slide an opening tool under this clip.

The position of the opening tool is shown on the first picture.

On the second picture I tried to show how the opening tool is able to slide under the clip (highlighted in green)

It is not easy to access. Therefore it is not easy to do. I also is not easy to take a picture of. So I added the third picture, hopefully you may see what you need on one of them.

Once the first clip is released, the other ones are easier to access.