To clear the fog in Expedition Robbie’s Farm, you need to ensure you have enough energy to proceed with the quests. The fog can be cleared by using the expedition tablet, which is located in the bottom-left corner of your screen. Through this tablet, you can build a path to the quest, which will help you navigate through the fog.

Here are some important points to remember:
- Make sure you have sufficient energy before attempting to build a path.
- Use the expedition tablet to find and build paths to quests.
- The amount of energy required may vary, so keep an eye on your resources.