Implementing login functionality using Clerk involves several steps. Here is a brief overview of the process:

1. **Create a Clerk Account**: The first step is to sign up for a Clerk account on their website. This will give you access to the Clerk Dashboard where you can set up your application.

2. **Set Up Your Application**: In the Clerk Dashboard, create a new application for the project where you want to implement the login functionality. You will receive a Client ID and Client Secret which you will need to integrate Clerk into your application.

3. **Integrate Clerk SDK**: Install the Clerk SDK in your front-end application (such as React, Angular, Vue.js) using npm or yarn. You will also need to add Clerk's script tag to your HTML file.

4. **Initialize Clerk**: In your front-end code, initialize Clerk with the Client ID obtained from the Clerk Dashboard. This will allow you to use Clerk's authentication and user management features.

5. **Add Login Components**: Clerk provides pre-built UI components like `SignIn`, `SignUp`, and `UserBadge` that you can add to your application. Customize these components to match your application's design and functionality.

6. **Handle Authentication**: Use Clerk's authentication methods to handle user sign-in, sign-out, and session management in your application. Clerk handles the entire authentication flow, including passwordless login, multi-factor authentication, and more.

Overall, implementing login using Clerk is a straightforward process with detailed documentation and support available on Clerk's website. For specific implementation details and code examples, refer to Clerk's official documentation and code samples.