3) Peter is playing a new video game with Tina.

Yes/No question:

Is Peter playing a new video game with Tina

Yes, he is.

Question about the subject of the verb:

Who is playing a new video game with Tina?

Peter.

Question about the action:

What is Peter doing?

He is playing a new video game with Tina.

Other questions:

Who is Peter playing a new video game with?

Tina.

What is Peter playing with Tina?

A new video game.

What kind of game is Peter playing with Tina?

A video game.

What kind of video game is Peter playing with Tina?

A new video game.