Once you recall the memory of the dead important dear person that you lost, you won't feel sad or in pain anymore! These feelings would be replaced by peace inside, something inside you has allowed the dead person to go in peace, there would be kind of reconciliation between you and his or her perpetual departure,
Only that time you could get rid of that sadness and grief.
Usually the feeling of grief differs
from person to anther one according to his own experience and according to the relation between him\her and his\her lost person, but usually it doesn't last longer, the feelings decreases by the time! It may takes 2 or 3 years but not many years,

This in case the loss isn't related by a feeling of guilt of course! Or a failure to perform a duty towards the lost person!
What steps u need to do! Tbh I still look for an answer! But the best step you have to do is to let them go in peace and to think that they are happy wherever they are, and they are somewhere watching you and smiling to you from the skies.