Attaching a model onto player's torso after clicking an GUI button?

I’m currently making an avatar editor for my survival game, and I wonder if there is any way to attach a model into player’s character by clicking a GUI button.

Oh, and also here’s the thingy that I am trying to attach.

So, the first idea that comes to mind is making it an accessory, then using Humanoid:AddAccessory. If it’s off a little bit, try messing with the mesh’s offset until it lines up properly with the character. If you don’t know how to make it an accessory, you can insert an accessory into the workspace and add it to the player that way

Another way would just be to weld it to the character, but it won’t appear as an accessory

Hey, I use WeldConstraints, I create a part that I position like how it should look when it’s inside the torso and weld it to the model using a WeldConstraint, then use that part to weld it to the character’s Torso.

BackPackModel.backPart.CFrame = torso.CFrame
BackPackModel.backPart.WeldConstraint.Part1 = root

image
This might not be the most efficient one but it’s the one I use