Open Messages on your iPhone or iPad
Open an existing conversation or start a new one
Tap the App Store icon next to the text field
Search for or select the game app you want to use
Download and install the game if needed
Return to the conversation and open the game app from the iMessage app drawer
Start a new game or accept an invite from the other person
Follow the on-screen instructions to take your turn
Send your move through iMessage
Wait for the other player to respond
Open the conversation again to continue playing when it is your turn