Yes, that sounds right. A couple of key points to make are that a) bounding boxes and anchor boxes are related but they are not the same thing and b) that bounding boxes do not have to be contained within a single grid cell. The grid cells are just used to organize the output by assigning the objects to the cell that contains their centroid.
This is a pretty deep topic. YOLO is by far the most complex algorithm we’ve encountered in any of the DLS courses so far. There are some great threads explaining YOLO in more detail that are worth a look. Here’s one to get started on the role of anchor boxes.