Start up the world with the seed 190800072 on Easy, with the bonus chest and coordinates turned on. Craft a sword, and make your way towards 440, 65, 460. This is the location of the Pillager Outpost. You can either make a bed to set your spawn here or copy a save of this world in case you die. You’ll know which one is the Pillager Captain because they have a large banner over their head. It’s best to attack him when he is alone away from the tower as his guards can be annoying to fight. Or you can release the caged Iron Golem and he will help attack. Just make sure he doesn't kill the captain. Once you kill the Captain, you will receive the Bad Omen effect, as well as an achievement.
Now head towards 560, 65, 520. This is the location of a village. Upon entering the village with the Bad Omen effect, a raid will commence, and you should get the achievement for starting a raid.