PX2 cudnn7 install problem

I installed the latest 5.05 PDK
It contains CUDA9.0
But without cudnn7, I downloaded a cudnn7 but how do I need to install it on PX2?

Dear Calmacar-Bao,
When you flash PX2 with PDK, it installs cudnn on PX2. Please check libcudnn.so at /usr/lib/aarch64-linux-gnu

Thanks
Sivaramakrishna