How to make a part inside a player's arm weld to it??

I've made a script that creates a part using Instance.new and I want to know how I could make that part like stick to the player's arm, when the player moves the part will remain stuck to the players arm. I was thinking welding but I am not sure..

local forearm = Instance.new("Part",game.Workspace.zle_n["Right Arm"])
forearm.CFrame = game.Workspace.zle_n["Right Arm"].CFrame + Vector3.new(0, -0.3, 0)
forearm.Anchored = true

Code is just in case someone could show me how I could maybe make it work