I don't know if this will be helpful to anyone, but ambient occlusion settings have moved since the video was recorded.
Using 3.1 and Cycles:
Render Properties Panel->Light Paths->Fast GI Approximation->AO Distance
In Blender 3.4 ... as mentioned by ppetermoldovia above.
Β Render Properties Panel > Light Paths > Fast GI Approximation > AO Distance
ALSO, change the Method from "Replace" to "Add".
