Living organisms are incredibly complex biological machines, working to continue life. However, at our core, we are pretty simple and have the same basic unit, the cell. Then many similar cells working together to perform the same function form a tissue. Now different tissues serve different function.
However, many different tissues working together to perform one major function is called an organ. Now the thing is that the cells are made of multiple different things. Breaking them down individually will leave us with proteins, fats, carbs and vitamins minerals and other stuff which are basically molecules. So, the order is molecule, cell, tissue, and organ.