So we synthesize this monoclonal antibody, we call the primary antibody that can bind to that antigen, the protein that we actually want to locate. Now, once we form the monoclonal antibody and once we run gelatrophrases, we then transfer that separated protein sample onto a polymer sheet. And this step is basically done to make it easier for us to work with our separated protein mixture. Now, the next step is to take this polymer sheet and we mix it with this antibody that we form in step one. And once we mix these two mixtures, this antibody, the primary antibody, it will basically bind onto the proteins found in one of these bands because one of these bands will contain that antigen that is specific for this protein. And so let's suppose it's the second band from the top that contains the proteins that we want to study.