Bad hub actually usually means bad bearings which are part of the hub unit and cannot be replace separatly.
To remove the hub, take off the wheel, caliper and rotor. Remove the dust cap from the hub. Under that cap is a 36mm nut torqued to 250 ft/lbs. (Yes, that is very tight!) Remove the nut and then the hub slides off the spindle.
It may be easiest to loosen the nut with the wheel back on the car.
A new nut/washer piece (available from Ford) should be used for installation and retorqued to the 250 ft/lb spec.