To use this feature:

• you will need to download the Google Messages app from the Play Store and set it as your default SMS app.
• You’ll see the “Set Default SMS App” button when you open it for the first time.
• Next screen or pop-up, select “Messages” and then tap “Set as default.”
• Every one of your past conversations will now appear in the Messages. Choose a conversation where you want to schedule a message.
• Enter the message you want to schedule and press the send icon for a long time.
• The local time is seen at the top so there would be no confusion as to when the message will be sent. You can choose “Pick Date and Time” from the present times.
• If you choose a custom date and time, you will be asked to select a date from the calendar and to select a time. Tap “Next” when you’re done.
• The time and date you have chosen will be shown again. To confirm your choices, tap “Save.”
• Last but not least, the scheduled date and time will appear above your message. To schedule a message, tap the send icon.
• You’re going to see the scheduled message in the conversation.
• Click the clock icon to alter the text message or the scheduled time, send it right now, or delete the message completely.