Here is a step-by-step guide on how to activate your UAN number:

1. Visit the official website of the Employees' Provident Fund Organization (EPFO) at www.epfindia.gov.in.

2. Click on the 'Activate UAN' option on the homepage.

3. Enter your UAN number, mobile number, and member ID in the required fields.

4. Click on the 'Get Authorization Pin' button.

5. You will receive an authorization PIN on your registered mobile number.

6. Enter the authorization PIN in the required field and click on the 'Submit' button.

Here are the steps you need to follow to withdraw your PF amount:

1. Check your eligibility: Ensure that you are eligible to withdraw your PF amount, which includes leaving your job and having an inactive account for two months or more, or retiring, becoming disabled, or passing away.

2. Get your UAN: Obtain your Universal Account Number (UAN) from your employer or the EPFO portal.

3. Log in to the EPFO portal: Log in to the EPFO portal using your UAN and password.