I'm playing a OoV human Paladin in a group of 5 characters all at 4th level. In addition to my paladin, we've got a gnome wizard, a human barbarian fighter and a dragonborn Bard. We are exploring a mine that have been invaded by a horde of undead. In the last session two Zombie Ogres and 5 zombies became aware of us, and we are about to do battle. It is my 3rd time playing DnD, so I've been researching what OoV Paladin's can do around 4th level. It is still a little unclear what Vow of Enmity does. The feature description states "Pick a target within 10 feet, gains advantage on attack rolls to hit." Does that mean I roll my 20 sided to hit then roll an addition dice like a 4d or 6d to the hit roll score? Does it mean I get to hit if I am 1 number short? Does it mean I get to reroll if I miss? Please explain........ My group is meeting in 5 hours and it would be great to know how to use it effectively.

Thanks!!

Advantage means you roll 2d20 (two twenty sided dice) and use the one that rolled higher when calculating to see if you hit. Conversely, Disadvantage means using the lowest. If at any time you would have both Advantage and Disadvantage on the same roll at the same time they cancel each other out and you have neither, no matter how many instances of each you might have.

What Sposta said. But here’s the rule

Sometimes a special ability or spell tells you that you have advantage or disadvantage on an ability check, a saving throw, or an attack roll. When that happens, you roll a second d20 when you make the roll. Use the higher of the two rolls if you have advantage, and use the lower roll if you have disadvantage. For example, if you have disadvantage and roll a 17 and a 5, you use the 5. If you instead have advantage and roll those numbers, you use the 17.

Cool, thanks!