I think we need a bit more information to know how to answer this. Are you talking about training a YOLO model or just using a YOLO model that has already been trained? If the latter, then there is nothing special you have to do other than perhaps resize the input image to the size and format that the model expects. A trained YOLO model takes individual images and returns the identifications of the objects it is able to recognize in each image, in the complex form described in the lectures and the assignment.
Training a YOLO model is (as you would expect) a much more complex task, given that it requires labelled images, which in the case of YOLO is pretty complex, including anchor boxes, bounding boxes (not the same thing) and object classes. There are a number of really great threads here on the forums about YOLO from one of our fellow students who has invested serious time and effort working with YOLO and has shared the knowledge gained. If you want to dig deeper than what you can learn from the lectures and the YOLO assignment, here’s a good thread to start with and it provides links to some of the others.