To start the web application you have to create your mongoDb Atlas account and cloudinary account and then setup an .env file in the backend folder with these entries

    PORT=
    MONGODB_URI=
    CORS_ORIGIN=*  # All for all urls
    ACCESS_TOKEN_SECRET = 
    ACCESS_TOKEN_EXPIRY = 
    REFRESH_TOKEN_SECRET = 
    REFRESH_TOKEN_EXPIRY = 
    CLOUDINARY_API_SECRET = 
    CLOUDINARY_API_KEY = 
    CLOUDINARY_API_NAME = 
To start backend: 
In backend folder: npm run start


To start Frontend: 
In frontend folder: npm run dev