How to assemble servo for GoPiGo 2?

My son and I have finally got our GoPiGo working. It is very old- a Gopigo2. We want to put the servo on, but can’t figure out how the pieces go together or how they mount onto the GoPiGo, and I’ve searched everywhere for instructions or even a decent photo that would help me understand how it goes together.
I’m sure this is straightforward and obvious for some people but not for us. Please direct me to the instructions I am failing to find on my own.

(GoPiGo3 user here, not DI)

The only thing I could find was an old video showing the servo mounted to a GoPiGo2.

It looks like you

  1. mount a “servo control horn” to the servo,
  2. then invert the servo, holding it shaft down toward the top plate of the GoPiGo2.
  3. Insert a screw through the control horn into the GoPiGo2 top plate.
  4. It appears there is a sensor plate that assembles around the servo body

Here is the video I found:

And another: (French but more pictures…)

Not good but best I could find: