Port forwarding problem

When i run the app by chainlit run app.py command it shows 2024-01-03 15:57:27 - Your app is available at http://localhost:8000 but from my machine nothing is opening in localhost. How i can forward sagemaker jupyterlab to my own machine. I have got one way of solution

ssh -i <key-file> -N -L 8000:localhost:8000 ubuntu@<public-ip-address>

But I am not able to find <key-file> for sagemaker jupyterlab instance. Please help me