In general, the students are allowed to borrow code from the DLStudio module for creating their homework solutions. Therefore, in order to best understand the solutions, you might first wish to become familiar with the DLStudio module.
For the homework on multi-instance object detection with YOLO-like networks, the students are allowed to borrow code from the Region Proposal Generator (RPG) module. Becoming familiar with the YOLO code in this module will help you understand the submitted homeworks better.
The best way to become familiar with the two modules mentioned above is to work your way through the examples in the various Examples subdirectories in the two module distributions, one for DLStudio and the other for RPG.