Animation not playing and not understanding length

I’m trying to make a crouch/dash that uses linear velocity to boost a player and runs an animation while the player is being moved forward. The problem is I don’t know how to adjust the length of my animation track and the animation isn’t working. I tried debugging it but what came up in my output was “:arrow_forward: Property “Animator.EvaluationThrottled” is not currently enabled. (x7)”. I also tried using the Roblox AI assistant and looking up the issue on google but I still don’t know how I can fix this.

Server script:

local debounce = false
game.ReplicatedStorage.RemoteEvent.OnServerEvent:Connect(function(plr)
	if not debounce then
		debounce = true
		local hum = plr.Character.Humanoid
		print(hum)
		local anim = Instance.new("Animation", plr)
		print(anim)
		anim.AnimationId = "http://www.roblox.com/asset/?id=15571376249"
		local animtrack = hum:LoadAnimation(anim)
		animtrack:Play()
		print(plr)
		local force = Instance.new("LinearVelocity", plr.Character)
		local attachment = Instance.new("Attachment", plr.Character.HumanoidRootPart)
		force.Attachment0 = attachment
		force.RelativeTo = Enum.ActuatorRelativeTo.Attachment0
		force.MaxForce = 12500
		force.VectorVelocity = Vector3.new(0,0,-12500)
		task.wait(0.5)
		force.VectorVelocity = Vector3.new(0,0,-10000)
		task.wait(0.5)
		force:Destroy()
		attachment:Destroy()
		task.wait(1)
		debounce = false
	end
end)

Local script:

local UIS = game:GetService("UserInputService")

UIS.InputBegan:Connect(function(input)
	if input.KeyCode == Enum.KeyCode.F then
		game.ReplicatedStorage.RemoteEvent:FireServer()
	end
end)

I got the animation to work but I don’t know how to adjust the length of the animation in script, would I need to use animator to adjust length?