Go to the folder 'backend-python-grpc',
Ensure that the requirements are installed as per the file 'requirements.txt' and run the following in the terminal:-

python server.py

Go to the folder 'frontend-next-client-server',
Install the node modules and other packages by running

npm install

Then run the NextJS application by typing the following in the terminal:-

npm run dev

Open https://localhost:3000 with your browser to see the running app.