Human: I want to build a composting toilet. What do I need to know? Assistant: 
You will need to decide what type of composting toilet you would like to use, such as an above-ground or below-ground system. Consider the size and shape of your yard, how much space you have available for the toilet, and any other factors that may affect your decision. Additionally, research different types of composting toilets to determine which one best suits your needs.