Free 3 months Apple TV when purchasing a new device

Hi,

I purchased 1 month ago a new iPhone (12 mini). The device alarmed that I deserve a 3 months free for Apple TV and Apple Arcade.

I couldn’t take care of it on that time and than it disappeared and I only have a notification for the Apple Arcade.

how can I join the Apple TV for free for the time I deserve?

what is Apple Arcade...?

thank you.