TT externals are fab,i have 3 of them,one being a 1200
Has said lots of media,the bottom tray is ceramic rings and a sponge,next one is i think is 2 more sponges,then bio balls,last & top basket holds another sponge,carbon bag & the filter floss.
All the media incl the balls/rings/sponges only needs a rinse in used tank water once its cycled.they will last for years,the first 2 will last for ever in theory,so dont ever change them
Just remember to rinse all media in warm water on set up,i'd leave out the carbon bag,not really necessary,and you may find it useful to add it later for removing meds or tannins from the tank in the future