The hub Puller tool is used to remove the rear hub/brake drum from the rear axle after removing the nut. Slip it over the flange on the hub and tighten the screw against the axle. You may have to use a hammer on the end of the bolt and/or apply some heat to the hub before the hub will come off the axle.
NOTE!!! Prior to using this tool, back off the service brake adjusting wedge and the emergency brake linkage. Failure to do this will result in damage to the brake shoes and emergency brake band.