On the Internet:
Visit the Meta Horizon+ page, log in and redeem the available titles.
In Your Headset:
Go into the Store and look for the Horizon+ icon on the top. This will take you to the Meta Horizon+ page. In the Monthly games section, you can see which apps are available and redeem them.
In the Meta Horizon app:
From the home screen tap on the Store icon in the upper left corner. Then tap on the Horizon+ icon where you will find the Meta Horizon+ page. In the Monthly games section, you can see which apps are available and redeem them.