Help with Calculating Projectile Motion

[GameMaster4268 (Game)]

So, I need help trying to calculate projectile motion:

The Module I am using for this:

PredictProjectile - Calculate projectile motions easily!

[predictprojectile icon] Have you ever wanted to make some kind of indicator to tell where your bullets would lead? Have you ever wanted to make your projectile-based game more easier for noobs as seen below? [Capture] Fear not! I have a solution for you! PredictProjectile PredictProjectile is a module that is very simple to use, and its API is relatively easy to understand. Here’s the RBXM: PredictProjectile.rbxm (1.6 KB) Here’s an example of using it: [Anti-aircraft AI demo vi…

local nextPosition = PredictProjectile:FindLeadShot(targetRoot.Position, targetRoot.AssemblyLinearVelocity, ToolData.BulletSpeed, characterRoot.Position, characterVelocity, ToolData.EffectGravity)
				script.FireProjectile:Fire(firePoint, nextPosition)

FastCast:

castBehavior.Acceleration = Vector3.new(0, -ToolData.EffectGravity, 0)

script.Parent.FireProjectile.Event:Connect(function(firePoint, hitPosition)
	castParams.FilterDescendantsInstances = {character, projectilesFolder}
	
	local orgin = firePoint.WorldPosition
	local direction = (hitPosition - orgin).Unit
	caster:Fire(orgin, direction, ToolData.BulletSpeed, castBehavior)
end)

ToolData:

local module = {
	BulletSpeed = 100,
	Projectile = Projectiles:WaitForChild("Arrow"),
	DebugMode = true,
	EffectGravity = 200,
	MaxDistance = 10000,
}

I want it to always hit the target.