loosen lug nuts, put jack under truck, raise jack, remove lug nuts, remove tire, replace tire, put lug nuts on, lower vehicle so tire touches ground, tighten lug nuts, lower jack all the way, remove jack, drive away
Jack the thing up, remove the lug nuts, take tire off, put new tire on, put lug nuts back on, tighten them up, lower the vehicle, then tighten them again.