You lift up your chest and place the silicone filling in your bra or bikini. Then you place your breasts so that the nipple can't fall out of the bra or bikini and the right push up is given from underneath.
Some bras and bikinis have a special placement for pads. Feel free to use the silicone padding as pads.
The bra padding is waterproof and can therefore also be worn as bikini pads.
The filling can easily be washed by hand with lukewarm water and a little soap. Simple and reusable.