Is this Correct for Distracking Strike?

[Bernie]

Distracting Strike - When you hit a creature with an attack roll, you can expend one Superiority Die to distract the target. Add the Superiority Die roll to the attack’s damage roll. The next attack roll against the target by an attacker other than you has Advantage if the attack is made before the start of your next turn.

67563

[Zacchaeus]

See my other post about the Power Group. (I should also mention that if you used the character wizard to create the character most of this should be set up for you).

For this one add another line to the power group and type Distracting Strike into the left hand box.

Right click on the line and add an effect of DMG: 1d8 set the targeting to self and the expend to on next roll. Apply this effect just before damage is rolled. Right click again and add effect and the effect will be GRANTADVATK. Set the targeting to Self (-> Targets) and the expend to on next roll and apply this effect to the next player who attacks this target. You could also just apply GRANTADVATK to the target with an expend of on next roll. The problem with the latter way of doing it is that it doesn't stop you from getting advantage on your next attack against the target.
You should end up with this.

67571

[Bernie]

Why use DMG: 1d8 vs. this in screenshot? 67582

[Zacchaeus]

Why use DMG: 1d8 vs. this in screenshot? 67582

Using the DMG: 1d8 effect adds a d8 of the same damage type that you deal with whatever weapon you use, so if the target has resistance or immunity to the damage type you are using all the damage will be correctly mitigated if you use DMG: 1d8 effect. In your image the damage is untyped and that will not get resisted and so you'll do the wrong damage. You could do it the way you show but you'd need to have a number of effects with all of the different damage types that the character could do. So using DMG: 1d8 effect is easier and more convenient.