Better way of adding and sticking parts to characters?

I'm new to scripting and still learning.

Okay, so when a player joins I want a Katana to be part of the player model.

I made this script for that to happen

sword = game.Lighting.Katana
weld = game.Lighting.Weld

game.Players.PlayerAdded:connect(function(player)
	player.CharacterAdded:connect(function(character)
		
		local NewSword = sword:Clone()
		NewSword.Parent = character
		local rotation = Vector3.new(0, 0, 0)
		
		NewSword.CFrame = character:WaitForChild("Left Leg").CFrame + Vector3.new(0.55, 0.4, 0) - Vector3.new(0, 0, 1.7)
		NewSword.Rotation = rotation + Vector3.new(170, 0, -90)
		
		local ImWeld = weld:Clone()
		ImWeld.Parent = character
	end)
end)

The problem is that player walking animation doesn't play/work.

GIF: https://gyazo.com/cd306ac2e402a5738e9cb678e2e6b535

I don't know much about welding or keeping parts together so I'm using a free model weld script to hold the player and the sword together, but I'm pretty sure that is what is stopping animation from playing. I also don't know much about cframe either.

Code of free model weld script

local all,last = {}
function scan(p)
	for _,v in pairs(p:GetChildren()) do
		if v:IsA("BasePart") and v.Name ~= "Wheel" then
			if (last) then
				local w = Instance.new("Weld")
				w.Part0,w.Part1 = last,v
				w.C0 = v.CFrame:toObjectSpace(last.CFrame):inverse()
				w.Parent = last
			end
			table.insert(all,v)
			last = v
		end
		scan(v)
	end
end
scan(script.Parent)
for _,v in pairs(all) do v.Anchored = false end 

And I'm wondering if there is a better way to keep a object/part on on the player

I made my own weld and welded the sword to "HumanoidRootPart" So the sword doesn't move with the leg animation.

If others need help with welding watch this video! - https://www.youtube.com/watch?v=eBMWLUAgNMs

Finished script

sword = game.Lighting.Katana
weld = game.Lighting.Weld

game.Players.PlayerAdded:connect(function(player)
	player.CharacterAdded:connect(function(character)
		local NewSword = sword:Clone()
		NewSword.Parent = character
		local LeftLeg = character:FindFirstChild("HumanoidRootPart")

		local rotation = Vector3.new(0, 0, 0)
		
		NewSword.CFrame = character:WaitForChild("Left Leg").CFrame + Vector3.new(0.55, 0.4, 0) - Vector3.new(0, 0, 1.7)
		NewSword.Rotation = rotation + Vector3.new(170, 0, -90)

		weld = Instance.new("Weld")
		weld.Part0 = LeftLeg
		weld.C0 = LeftLeg.CFrame:inverse()
		weld.Part1 = NewSword
		weld.C1 = NewSword.CFrame:inverse()
		weld.Parent = NewSword

		NewSword.CanCollide = false
		

	end)
end)