Adding a detection head to vision transformer output?

I am working on this model for object detection using ViT where I want to add a detection head to my decoder so that I can get bounding boxes. The output feature tensor of my decoder is of dim (12,96,224,224) where batch size = 12, no. of features per pixel = 96 and the image is of size (224,224).

How do I take this feature map and annotations and pass them through a CNN to obtain multiple bounding boxes?

Edit: …

computervision detection head transformer vision