The 5-step approach to grievance handling involves: 1) identifying the problem, 2) investigating through interviews and collecting facts, 3) documenting all information, 4) preparing evidence and writing the grievance, and 5) presenting the grievance to management. Preparation, the fourth step, is key and involves reviewing evidence, determining relevance, distinguishing facts from opinions, researching past grievances, discussing with representatives, writing the grievance form ensuring it states the desired remedy, and preparing the grievant for the meeting.