Complex sentence: On January 1,2018, John Cena announced his participation in the match via Twitter, and on "Raw" that same day, Finn Bálor announced his participation in the match.
Split into simpler sentences: On January 1,2018, John Cena announced his participation in the match on Twitter. On the January 1,2018 episode of "Raw", Finn Bálor announced his participation in the match.