Bromeliads in need to be planted can be best put in an airy soil, like orchid earth.
Species that need to be off the ground, which most are, can be pinned to the back wall,wood or anything you like.
You may use a variety of things to keep them up until they rooted, some wire,rope,silicone or the staples sometimes used in aquaria.
But you first need to know what type of bromeliad it is you are planning to buy.