Place it at the very opening of a class recap or reunion edit, before any recap footage, then let the main segment run, and save a baby laughing meme sound for an outtake at the end once the credits finish.
關於此聲音
This clip is a short spoken greeting in Portuguese, a voice saying boa tarde to Turma 21 as a class welcome. It feels warm and upbeat, like the start of a lesson where everyone is arriving at once and settling in together. The greeting is presented as a welcome from Lets.