How do I get my bonus for being invited to the game?

Invitation bonuses are awarded in stages. The more you play, the faster you can get them.

Enter the ID of your friend in the special field in the "Friends" → "Invitations" tab. Your friend must then confirm the invitation.

You can claim your rewards in the same tab. You will get the remaining bonuses once you reach levels 5, 10, and 20.