How can I use my free ticket in Bingo?

How can I use my free ticket in Bingo?

A message in the bingo room will tell you in which game you can use your ticket in. The message will also tell you how long it's valid.

If you receive a coupon as a gift for the Bingo Variant, for example, you can only use it there. Press the "Use" button to redeem your coupon.