1. To open Gmail Go to https://www.gmail.com
2. Click on sign in as shown in the below image

3. Enter your Gmail id and password in the textbox (refer below image)

4. Click the Compose button as shown in the below image

5. Click the dropdown arrow as shown in the below image.

5.1. Click on Schedule send as shown in the below image

6. Click on pick date and time as shown in the below image

7. Set date and time and click on Schedule send as shown in the below image

8. View Scheduled email as shown in the below image

Wow!

Your email will go to the recipient as per the schedule.