Start with the cue ball anywhere behind the baulk line. The traditional "D" isn't used in World Eight Ball rules.
The rules want to encourage an open game - so, to make a legal break, you have to hit the pack and get at least four different balls (cue ball not included) to hit a cushion. In other words, you're going to have to hit the pack hard!
An alternative legal break is to pot a ball - in which case, it doesn't matter how many other balls have hit a cushion - it's a legal break.
If you haven't managed to get four balls to a cushion, nor have you managed to pot a ball, then it's a foul break.
The balls are re-racked, your opponent breaks-off, and they have two visits. But they're also required to make a legal break.
It's a re-rack, and you break again, with just one visit. This applies even if the cue ball has been potted as well, and even if four balls haven't hit a cushion.
If, apart from the cue ball going down, you've made a legal break (i.e. either four balls have hit a cushion, or you've potted another ball, apart from the white) then it's your opponent's turn - but with just one visit. They will play from where the balls stand.
If you haven't got four balls to a cushion, or potted a ball, then it's a foul break. The balls are re-racked, your opponent breaks-off, and they have two visits. But they're also required to make a legal break.
Before going any further, you must nominate a colour. You can choose to stick with the colour you've potted, or you can swap to the other colour - it's your choice.
If you play a shot without nominating, then it will be a foul - your opponent will get two visits with an open table.