Deepstream-app: error while loading shared libraries: libnvinfer.so.6: cannot open shared object file + ubuntu 18.04

@Amycao, I have downloaded the docker image DeepStream | NVIDIA NGC and tried to run the C samples. Now this docker image have all required Cuda and TensorRT versions for Deepstream 4.0.2. Still the C samples are not working.

$ deepstream-app -c ~/deepstream_sdk_v4.0.2_x86_64/samples/configs/deepstream-app/config_infer_primary.txt

** ERROR: <create_multi_source_bin:714>: Failed to create element 'src_bin_muxer'
** ERROR: <create_multi_source_bin:777>: create_multi_source_bin failed
** ERROR: <create_pipeline:1045>: create_pipeline failed
** ERROR: <main:632>: Failed to create pipeline
Quitting
App run failed

And when tried to run Python samples, got below error:

$ python3 deepstream_test_1.py ~/deepstream_sdk_v4.0.2_x86_64/samples/streams/sample_720p.h264

Creating Pipeline 
 
Creating Source 
 
Creating H264Parser 

Creating Decoder 

 Unable to create Nvv4l2 Decoder 
 Unable to create NvStreamMux 
 Unable to create pgie 
 Unable to create nvvidconv 
Creating EGLSink 

Playing file /root/deepstream_sdk_v4.0.2_x86_64/samples/streams/sample_720p.h264 
Traceback (most recent call last):
  File "deepstream_test_1.py", line 263, in <module>
    sys.exit(main(sys.argv))
  File "deepstream_test_1.py", line 196, in main
    streammux.set_property('width', 1920)
AttributeError: 'NoneType' object has no attribute 'set_property'

When I downloaded the docker, install.sh was missing from deepstream sdk folder and I already tried to clear the cache sudo rm ${HOME}/.cache/gstreamer-1.0/registry.x86_64.bin

Please help me to setup deepstream setup at least in this docker image on my Ubuntu 18.04 Desktop.

Thanks,
Archana