How should I install my new UGGs replacement insoles?

I just brought some replacement insoles for my Uggs but have no clue how to install them. Can anyone help me? Should i just insert them on top of the old ones?How should I install my new UGGs replacement insoles?The old insoles are glued down to the soles and you cant pull the old ones out so i just put the new ones in over the old one.It feels wierd at first till they get broken in.