I think the missing video might have been lost in one of the database crashes…and the creator is no longer available.
IF you want to see a good video on setting up the rest of the controllers check out Bret’s biped rigging series, which is essentially the same thing, but without the mesh deformer.
In the interim, I would recommend downloading the project file from the “weight testing” video, and then explore the controller hierarchy.
The hands and feet should be fairly self apparent, as it is simply placing nulls under the controllers.
The thing that is less apparent is the pelvis, spine, and head.
For these you need to create a PSR constraint on the Pelvis, Spine, and Neck joints.
In the tags, the Pelvis.CON should be linked to the Pelvis joint, the Spine.CON should be linked to the Spine joint, and the Neck.CON gets linked to the Neck joint