Setting up an “Out of Office” or vacation responder in Gmail is a great way to let people know that you won’t be able to reply to emails immediately. Whether you’re planning to disconnect on a holiday or simply won’t have access to your email for a while, Gmail provides an easy way to set up an automated response on both mobile and desktop platforms.

To Set Out of Office in Gmail on Desktop:

1. Open Gmail: Log into your Gmail account on your computer.

2. Settings Access: Click on the gear icon in the upper right corner of the page to access settings.

3. See All Settings: In the dropdown menu, select ‘See all settings’.

4. Go to General Tab: By default, you are likely already in the ‘General’ tab within settings.

5. Scroll Down to Vacation Responder: In the ‘General’ tab, scroll down until you find the ‘Vacation responder’ section.

6. Activate Vacation Responder: Click on ‘Vacation responder on’.

7. Set Date Range: Choose the start and end dates for when your out-of-office messages will be sent automatically.

8. Compose Your Message: Enter the subject and body of your out-of-office message in the fields provided.

9. Contacts Only Option: If you wish, select ‘Send responses only to people in my Contacts’.

10. Save Changes: Scroll down to the bottom of the page and click ‘Save Changes’.

Your out-of-office auto-reply is now active, and emails received within this date range will get your specified automated response.

To Set Out of Office in Gmail on Mobile:

1. Open Gmail App: Open the Gmail app on your mobile device.

2. Menu Navigation: Tap on the menu icon (three horizontal lines) which is usually located at the top left corner of your screen.

3. Scroll To Settings: Scroll down within this menu and find ‘Settings’. Tap on it.

4. Select Your Account: If you have multiple accounts, select the one for which you want to set up an out-of-office reply.

5. Out-of-Office Responder Option: Tap on ‘Vacation responder’.

6. Switch Toggle On: Turn on the Vacation Responder by toggling it on.

7. Set Date Range and Message: Set your start and end dates as well as compose your out-of-office subject line and message body just like on desktop.

8. Save Settings: Save these settings by tapping ‘Done’ or the appropriate save option depending on your mobile device’s operating system.

With these steps completed, Gmail will send out automatic replies as per your set preferences, ensuring that senders are informed about your availability without delay. Remember that it’s courteous for an out-of-office email to include information about when you’ll be able to reply or who to contact if immediate assistance is required during your absence.