So the antibody specific to the antigen that we're testing for is attached to the bottom of the well. And then we take our sample, for example, the blood sample, or it could be a urine sample, and we place it into our mixture. And if the antigen is present in that mixture, it will bind to our antibody that is coated on the surface of our well. So we form the antibody antigen complex. And now in step C, we add that enzyme linked antibody that we synthesized in the laboratory setting, and we place it into our well. And if the antibody antigen complex is present, if this complex exists, then the green antibody that contains the enzyme E will essentially bind to that antigen.