How can I use tween service on motor6d?

How can I use tween service on motor6d? My goal is making character T-pose, also I have to know how to make head upwards using tween service on motor6d

local SetPoseTo = {}
SetPoseTo.C0 = CFrame.new() * CFrame.Angles(0, 0, math.rad(90))
TweenService:Create(RShoulder.C0, TweenInfo.new(0), SetPoseTo):Play()

I tried this but got error

You have to define the Instance that you want to tween in the #1 argument, not defining the instance’s property. For example,

TweenService:Create(RShoulder, _, _)

Then you can tween the properties like this

local Pose = {
    C0 = CFrame.new(0,0,0)
}

local Info = TweenInfo.new(1)

TweenService:Create(RShoulder, Info, Pose):Play()

It works but Arm’s position goes kinda weird(it goes back of character torso)
How can I fix this?

try using it on X or Y axis

even I only use C0 = CFrame.new(0,0,0), arm just goes to weird position…

it is because the original C0 cframe was already offsetted.