In order to send messages automatically you need to setup a Personal Automation task that runs the Scheduled Automation Shortcut. Follow these steps after you've installed the Scheduled app and the Scheduled Automation Shortcut.
Before going through these steps, please make sure you've already:
Installed the Scheduled App
Bought a valid Premium Subscription
Installed the Scheduled Automation Shortcut
Have you gone through all of these steps? Yeah! Then you're ready for this:
Create a Personal Automation
Step 1: Open the Shortcuts iOS app -> "Create Personal Automation".
Step 2: Select “Time of Day”
NOTE: Change the date/time at “Time of Day” to configure the date/time you would like to send your messages.
Step 3: Select “Add Action” and search for the "Shortcut" iOS app.
Step 3: Search & Select “Run Shortcut”
Step 4: Select the Scheduled Shortcut: “Scheduled Automation”
Step 5: Disable “Ask Before Running”.
This step is very important! Other wise the Scheduled will not send the messages automaticcly. But you will get a push notification with a consent to run the shortcut.
Step 6: Schedule your first automated message. When you've scheduled a message and it runs for the first time, then the Shortcut app will ask to accept Privacy permissions. Please select "Always Allow", other wise it will ask you everytime you schedule a message.
NOTE: Accepting the privacy settings should only need to be done once, but it should be done per send service. So one time for iMessage, one time for WhatsApp, One time for Telegram, etc.
Sometime there is a bug in iOS where your Personal Automation doesn't run. Please check this article when this is the case: My Personal Automation doesn't run
You can find Step 1 till 5 in the video below: