How can I restore messages from iCloud to my iPhone?

My husband wants to restore the messages from his iCloud back onto his phone. From his phone when we go to settings, then iCloud, then messages, it's says 37.7MB. We click that box on this page it says "In iCloud 1,522 messages." So we don't understand a lot of the terminology and don't know what kind of device we need to restore these and I keep getting all kinds of answers.

[Re-Titled by Moderator]