Here's a brief overview of accomplishment:

Navbar: The navbar component provides navigation options for users to move around the application easily. It typically includes links to important pages such as home, listings, user profile, and perhaps a search bar. You can implement it using React components styled with Material-UI for a sleek and responsive design.

Login: The login functionality allows users to authenticate themselves before accessing protected resources or performing actions like adding new products.

Users should be able to input their credentials (username/email and password) and submit them securely to the server for verification. Once authenticated, the server issues a JWT (JSON Web Token) to the client, which can then be used to authorize subsequent requests.

You can implement login using a combination of React components for the UI, Node.js and Express for the backend logic, MongoDB for storing user credentials, and JWT for authentication.

Product Adding:

Product adding functionality allows authorized users (e.g., administrators or property owners) to add new rental properties to the system. This involves creating a form where users can input details such as property name, description, location, amenities, price, and images. Once submitted, the data is sent to the server, where it's validated and stored in the MongoDB database. You'll need to implement client-side validation to ensure that the data entered by users is correct before submitting it to the server.

Additionally, you may want to incorporate file uploading functionality to allow users to upload images of the property. For each of these components, you'll need to implement both frontend and backend logic. React and Material-UI will handle the frontend UI components and styling, while Node.js, Express, MongoDB, and JWT will power the backend functionality, including authentication, data storage, and API endpoints for handling requests. Redux can be used to manage the application state, especially for components like login, where state management is crucial.