Please download
https://ngc.nvidia.com/catalog/models/nvidia:tlt_pretrained_object_detection/files?version=darknet53 or
https://ngc.nvidia.com/catalog/models/nvidia:tlt_pretrained_object_detection/files?version=darknet19
as a pretrained model and train with your own data.
The link a hdf5 file. After training, you will get a tlt model.