So how exaclty do I tell if a position in 3D is on the left or right side of client's screen?

I’m trying to get a position in 3D and detecting if its to the left or to the left o the screen, im just kinda confused how to do this?

Something like this:

local camera = workspace.CurrentCamera

local screenPos, inViewport = camera:WorldToViewportPoint( yourWorldPoint )

if not inViewport then
    -- not on screen

elseif screenPos.X < camera.ViewportSize.X/2 then
    -- on the left
else
    -- on the right
end