Simplify the following text for a Grade 10 native English-speaking person.
Original: It was then announced that the main event at Backlash would be John Cena versus Triple H versus Edge in a Triple Threat match for the WWE Championship . At Backlash , Cena won the match and retained the WWE Championship via pinfall on Triple H with a Jackknife roll-up , but after the match Triple H attacked Cena , Edge and the referee with a sledgehammer and did a couple of DX crotch crops to Cena and Edge .
Simplified: It was then announced that the main event at Backlash would be a Triple Threat match for the WWE Championship between Cena , Edge and Triple H. At Backlash , Cena won the match and retained the WWE Championship via pinfall on Triple H with a jackknife roll-up , but after the match , Triple H attacked Cena , Edge and the referee with a sledgehammer .