To set an Out of Office or Vacation Responder in Gmail, follow these steps:

1. Open Gmail: Go to mail.google.com and log in if you haven’t already.

2. Go to Settings:

   • Click on the gear icon in the top right corner.

   • Select See all settings from the dropdown menu.

3. Navigate to the Vacation Responder:

   • In the General tab, scroll down to Vacation responder.

4. Turn on the Vacation Responder:

   • Select Vacation responder on.

   • Enter the start date and, optionally, the end date for your out-of-office message.

   • Type in the subject and message you want to send as your auto-reply.

5. Optional: Check the box for Only send a response to people in my Contacts if you want to limit who receives the auto-reply.

6. Save Changes:

   • Once done, scroll to the bottom and click Save Changes.

Your vacation responder will automatically turn on and send your custom reply during the specified time.