Etydhv

I'm new to dnd 5e, I was thinking that a martial adept superiority die could be used to make a thrown weapon disarm targets if used in conjunction with the conjure barrage spell.

From the book...

Martial adept:
You have martial training that allows you to perform special combat maneuvers. You gain the following benefits:

-You learn two maneuvers of your choice from among those available to the Battle Master archetype in the fighter class. If a maneuver you use requires your target to make a saving throw to resist the maneuver's effects, the saving throw DC equals 8 + your proficiency bonus + your Strength or Dexterity modifier (your choice).

-You gain one superiority die, which is a d6 (this die is added to any superiority dice you have from another source). This die is used to fuel your maneuvers. A superiority die is expended when you use it. You regain your expended superiority dice when you finish a short or long rest.

Trip Attack
When you hit a creature with a weapon attack, you can expend one superiority die to attempt to knock the target down. You add the superiority die to the attack’s damage roll, and if the target is Large or smaller, it must make a Strength saving throw. On a failed save, you knock the target prone.

Disarming Attack
When you hit a creature with a weapon attack, you can expend one superiority die to attempt to disarm the target, forcing it to drop one item of your choice that it’s holding. You add the superiority die to the attack’s damage roll, and the target must make a Strength saving throw. On a failed save, it drops the object you choose. The object lands at its feet.

Conjure Barrage
You throw a nonmagical weapon or fire a piece of nonmagical ammunition into the air to create a cone of identical weapons that shoot forward and then disappear. Each creature in a 60-foot cone must succeed on a Dexterity saving throw. A creature takes 3d8 damage on a failed save, or half as much damage on a successful one. The damage type is the same as that of the weapon or ammunition used as a component.

Can these two work as one together? If not, why not?

These abilities do not combine.

All Maneauvers require you to "hit a creature with a weapon attack". But Conjure Barrage is not a weapon attack, it is a spell. Requiring you to use a weapon does not automatically make something a weapon attack - you need at least an attack roll to be able to qualify as a weapon attack and apply a Maneauver.

Then, even if you do have an ability that lets you make lots of attacks against lots of targets, you still wouldn't be able to multi-disarm anyone. You can only use a single Maneauver per attack, and it triggers off of "hitting with a weapon attack", so you'd need to pick a single target to suffer the disarm and extra damage.