How do i remove stock cd player

so i already bought the "U" device but they keep sliding out. i have the alpine premium sound system so someone told me there is something securing it elsewhere. any ideas? 99 lincoln nav

forget all that just do it good ol' ghetto way sticka screw driver in on the sides slide it out and pull i use to do it before i got my indash

update... the device worked just wasnt hitting properly.