The old, displaced grease will begin to flow back out the cap around the grease gun nozzle. When the new, clean grease is observed, remove the grease gun and wipe off any excess. Otherwise, the chance of grease getting on brake linings is greatly increased. Then loosen the spindle nut to remove the torque. Do not rotate the hub.
Finger tighten the spindle nut until just snug.
Back the spindle nut out slightly until the first castellation lines up with the locking tang hole and insert tang. Nut should be free to move with only restraint being the locking tang.