You can do it like this
(Copied from my script)
local sx,sy = guiGetScreenSize()
local px,py = 1152,864 -- your resolution
local x,y = (sx/px), (sy/py)
BeerLabel:setBounds(x*64,y*27,x*91,y*15)
ColaIMG:setBounds(x*10,y*96,x*43,y*47)
Bar:setBounds(x*235,y*236,x*548,y*396)