Sending on Messages App via AppleScript

Trying to determine what’s wrong with the script below, I don’t know if I placed the phone number in the right place. Can someone help and show me where to place the number and in what format within the script?

on run {targetPhoneNumber, targetMessageToSend}
	tell application "Messages"
		set targetService to 1st service whose service type = iMessage
		set targetBuddy to buddy "+1 555 555 5555" of targetService
		set targetMessage to "Where are you?"
		send targetMessage to targetBuddy
		say targetMessage
	end tell
end run

Model: 2009 iMac
AppleScript: 2.7
Browser: Safari 537.36
Operating System: macOS 10.14