Help With Understanding Weld C0 and C1 When Welding Accessories

I used this function when creating code to attach an accessory to a character’s hand locally.
attach1 is the character’s RightGripAttachment, and attach2 is the accessory’s attachment. I understand welds in general, but I don’t understand why setting the weld’s C0 to the first attachment’s CFrame and C1 to the second attachment’s CFrame makes the accessory oriented correctly.
Could someone please give an explanation? (I don’t understand CFrame maths much)

local function weldAttachments(attach1, attach2)
	local weld ="Weld")
	weld.Part0 = attach1.Parent
	weld.Part1 = attach2.Parent
	weld.C0 = attach1.CFrame
	weld.C1 = attach2.CFrame
	weld.Parent = attach1.Parent
	return weld


C0 is the start point and C1 is the end point

C0 is the start point and C1 is the end point

like thes