Cricket is basically a simple game - score more than the opposition.
Two teams, both with 11 players, take it in turns to bat and bowl.
When one team is batting, they try and score as many runs as they can by hitting the ball around an oval field.
The other team must get them out by bowling the ball overarm at the stumps, which are at either end of a 22-yard area called a wicket.
The bowling team can get the batsmen out by hitting the stumps or catching the ball.
Once the batting team is all out, the teams swap over and they then become the bowling side.
Each time a team bats it is known as their innings. Teams can have one or two innings depending on how long there is to play.
The Ashes Test matches are over five days so England and Australia have two innings each to score as many runs as they can.
Whoever scores the most runs wins. But a cricket match can be drawn too.
That happens when the team bowling last fails to get all the batsmen out.