Can't Use Items in Inventory, Hands, or Vicinity

Hi, actions in DayZ are specific in a way that for most actions you need to have the item you want to use in your hands, and then either have a direct action or combine the item with something in the world or your inventory. These actions should all be highlighted via the HUD in the world. Do you see those UI prompts (e.g. hold left mouse button to eat when you have an apple in hands)? If yes, pressing the left mouse button does nothing for you? Do I understand your problem correctly?